Merge pull request #127 from jihoonson/fix-k8s-0.21.0

Fix link to the k8s extension and add it in the extension list
diff --git a/docs/0.21.0/development/extensions-core/druid-kubernetes.html b/docs/0.21.0/development/extensions-core/kubernetes.html
similarity index 92%
rename from docs/0.21.0/development/extensions-core/druid-kubernetes.html
rename to docs/0.21.0/development/extensions-core/kubernetes.html
index 11470dc..9a2436c 100644
--- a/docs/0.21.0/development/extensions-core/druid-kubernetes.html
+++ b/docs/0.21.0/development/extensions-core/kubernetes.html
@@ -1,4 +1,4 @@
-<!DOCTYPE html><html lang="en"><head><meta charSet="utf-8"/><meta http-equiv="X-UA-Compatible" content="IE=edge"/><title>Kubernetes · Apache Druid</title><meta name="viewport" content="width=device-width"/><link rel="canonical" href="https://druid.apache.org/docs/0.21.0/development/extensions-core/druid-kubernetes.html"/><meta name="generator" content="Docusaurus"/><meta name="description" content="&lt;!--"/><meta name="docsearch:language" content="en"/><meta name="docsearch:version" content="0.21.0" /><meta property="og:title" content="Kubernetes · Apache Druid"/><meta property="og:type" content="website"/><meta property="og:url" content="https://druid.apache.org/index.html"/><meta property="og:description" content="&lt;!--"/><meta property="og:image" content="https://druid.apache.org/img/druid_nav.png"/><meta name="twitter:card" content="summary"/><meta name="twitter:image" content="https://druid.apache.org/img/druid_nav.png"/><link rel="shortcut icon" href="/img/favicon.png"/><link rel="stylesheet" href="https://cdn.jsdelivr.net/docsearch.js/1/docsearch.min.css"/><link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.12.0/styles/default.min.css"/><script async="" src="https://www.googletagmanager.com/gtag/js?id=UA-131010415-1"></script><script>
+<!DOCTYPE html><html lang="en"><head><meta charSet="utf-8"/><meta http-equiv="X-UA-Compatible" content="IE=edge"/><title>Kubernetes · Apache Druid</title><meta name="viewport" content="width=device-width"/><link rel="canonical" href="https://druid.apache.org/docs/0.21.0/development/extensions-core/kubernetes.html"/><meta name="generator" content="Docusaurus"/><meta name="description" content="&lt;!--"/><meta name="docsearch:language" content="en"/><meta name="docsearch:version" content="0.21.0" /><meta property="og:title" content="Kubernetes · Apache Druid"/><meta property="og:type" content="website"/><meta property="og:url" content="https://druid.apache.org/index.html"/><meta property="og:description" content="&lt;!--"/><meta property="og:image" content="https://druid.apache.org/img/druid_nav.png"/><meta name="twitter:card" content="summary"/><meta name="twitter:image" content="https://druid.apache.org/img/druid_nav.png"/><link rel="shortcut icon" href="/img/favicon.png"/><link rel="stylesheet" href="https://cdn.jsdelivr.net/docsearch.js/1/docsearch.min.css"/><link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.12.0/styles/default.min.css"/><script async="" src="https://www.googletagmanager.com/gtag/js?id=UA-131010415-1"></script><script>
               window.dataLayer = window.dataLayer || [];
               function gtag(){dataLayer.push(arguments); }
               gtag('js', new Date());
diff --git a/docs/0.21.0/development/extensions.html b/docs/0.21.0/development/extensions.html
index 90a83a4..3e6dba6 100644
--- a/docs/0.21.0/development/extensions.html
+++ b/docs/0.21.0/development/extensions.html
@@ -115,6 +115,7 @@
 <tr><td>postgresql-metadata-storage</td><td>PostgreSQL metadata store.</td><td><a href="/docs/0.21.0/development/extensions-core/postgresql.html">link</a></td></tr>
 <tr><td>simple-client-sslcontext</td><td>Simple SSLContext provider module to be used by Druid's internal HttpClient when talking to other Druid processes over HTTPS.</td><td><a href="/docs/0.21.0/development/extensions-core/simple-client-sslcontext.html">link</a></td></tr>
 <tr><td>druid-pac4j</td><td>OpenID Connect authentication for druid processes.</td><td><a href="/docs/0.21.0/development/extensions-core/druid-pac4j.html">link</a></td></tr>
+<tr><td>druid-kubernetes-extensions</td><td>Druid cluster deployment on Kubernetes without Zookeeper.</td><td><a href="/docs/0.21.0/development/extensions-core/kubernetes.html">link</a></td></tr>
 </tbody>
 </table>
 <h2><a class="anchor" aria-hidden="true" id="community-extensions"></a><a href="#community-extensions" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Community extensions</h2>
diff --git a/docs/0.21.0/operations/kubernetes.html b/docs/0.21.0/operations/kubernetes.html
index f4af24e..0acff4f 100644
--- a/docs/0.21.0/operations/kubernetes.html
+++ b/docs/0.21.0/operations/kubernetes.html
@@ -25,7 +25,7 @@
 <pre><code class="hljs">$docker pull apache/druid:<span class="hljs-number">0.16</span><span class="hljs-number">.0</span>-incubating
 </code></pre>
 <p><a href="https://github.com/druid-io/druid-operator">druid-operator</a> can be used to manage a Druid cluster on <a href="https://kubernetes.io/">Kubernetes</a> .</p>
-<p>Druid clusters deployed on Kubernetes can function without Zookeeper using <a href="/docs/0.21.0/development/extensions-core/druid-kubernetes.html">druid–kubernetes-extensions</a> .</p>
+<p>Druid clusters deployed on Kubernetes can function without Zookeeper using <a href="/docs/0.21.0/development/extensions-core/kubernetes.html">druid–kubernetes-extensions</a> .</p>
 </span></div></article></div><div class="docs-prevnext"></div></div></div><nav class="onPageNav"></nav></div><footer class="nav-footer druid-footer" id="footer"><div class="container"><div class="text-center"><p><a href="/technology">Technology</a> · <a href="/use-cases">Use Cases</a> · <a href="/druid-powered">Powered by Druid</a> · <a href="/docs/0.21.0/latest">Docs</a> · <a href="/community/">Community</a> · <a href="/downloads.html">Download</a> · <a href="/faq">FAQ</a></p></div><div class="text-center"><a title="Join the user group" href="https://groups.google.com/forum/#!forum/druid-user" target="_blank"><span class="fa fa-comments"></span></a> · <a title="Follow Druid" href="https://twitter.com/druidio" target="_blank"><span class="fab fa-twitter"></span></a> · <a title="Download via Apache" href="https://www.apache.org/dyn/closer.cgi?path=/incubator/druid/{{ site.druid_versions[0].versions[0].version }}/apache-druid-{{ site.druid_versions[0].versions[0].version }}-bin.tar.gz" target="_blank"><span class="fas fa-feather"></span></a> · <a title="GitHub" href="https://github.com/apache/druid" target="_blank"><span class="fab fa-github"></span></a></div><div class="text-center license">Copyright © 2019 <a href="https://www.apache.org/" target="_blank">Apache Software Foundation</a>.<br/>Except where otherwise noted, licensed under <a rel="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA 4.0</a>.<br/>Apache Druid, Druid, and the Druid logo are either registered trademarks or trademarks of The Apache Software Foundation in the United States and other countries.</div></div></footer></div><script type="text/javascript" src="https://cdn.jsdelivr.net/docsearch.js/1/docsearch.min.js"></script><script>
                 document.addEventListener('keyup', function(e) {
                   if (e.target !== document.body) {
diff --git a/docs/latest/development/extensions-core/druid-kubernetes.html b/docs/latest/development/extensions-core/kubernetes.html
similarity index 92%
rename from docs/latest/development/extensions-core/druid-kubernetes.html
rename to docs/latest/development/extensions-core/kubernetes.html
index 81312ae..ff5cf49 100644
--- a/docs/latest/development/extensions-core/druid-kubernetes.html
+++ b/docs/latest/development/extensions-core/kubernetes.html
@@ -1,4 +1,4 @@
-<!DOCTYPE html><html lang="en"><head><meta charSet="utf-8"/><meta http-equiv="X-UA-Compatible" content="IE=edge"/><title>Kubernetes · Apache Druid</title><meta name="viewport" content="width=device-width"/><link rel="canonical" href="https://druid.apache.org/docs/latest/development/extensions-core/druid-kubernetes.html"/><meta name="generator" content="Docusaurus"/><meta name="description" content="&lt;!--"/><meta name="docsearch:language" content="en"/><meta name="docsearch:version" content="0.21.0" /><meta property="og:title" content="Kubernetes · Apache Druid"/><meta property="og:type" content="website"/><meta property="og:url" content="https://druid.apache.org/index.html"/><meta property="og:description" content="&lt;!--"/><meta property="og:image" content="https://druid.apache.org/img/druid_nav.png"/><meta name="twitter:card" content="summary"/><meta name="twitter:image" content="https://druid.apache.org/img/druid_nav.png"/><link rel="shortcut icon" href="/img/favicon.png"/><link rel="stylesheet" href="https://cdn.jsdelivr.net/docsearch.js/1/docsearch.min.css"/><link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.12.0/styles/default.min.css"/><script async="" src="https://www.googletagmanager.com/gtag/js?id=UA-131010415-1"></script><script>
+<!DOCTYPE html><html lang="en"><head><meta charSet="utf-8"/><meta http-equiv="X-UA-Compatible" content="IE=edge"/><title>Kubernetes · Apache Druid</title><meta name="viewport" content="width=device-width"/><link rel="canonical" href="https://druid.apache.org/docs/latest/development/extensions-core/kubernetes.html"/><meta name="generator" content="Docusaurus"/><meta name="description" content="&lt;!--"/><meta name="docsearch:language" content="en"/><meta name="docsearch:version" content="0.21.0" /><meta property="og:title" content="Kubernetes · Apache Druid"/><meta property="og:type" content="website"/><meta property="og:url" content="https://druid.apache.org/index.html"/><meta property="og:description" content="&lt;!--"/><meta property="og:image" content="https://druid.apache.org/img/druid_nav.png"/><meta name="twitter:card" content="summary"/><meta name="twitter:image" content="https://druid.apache.org/img/druid_nav.png"/><link rel="shortcut icon" href="/img/favicon.png"/><link rel="stylesheet" href="https://cdn.jsdelivr.net/docsearch.js/1/docsearch.min.css"/><link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.12.0/styles/default.min.css"/><script async="" src="https://www.googletagmanager.com/gtag/js?id=UA-131010415-1"></script><script>
               window.dataLayer = window.dataLayer || [];
               function gtag(){dataLayer.push(arguments); }
               gtag('js', new Date());
diff --git a/docs/latest/development/extensions.html b/docs/latest/development/extensions.html
index 6cc05a0..d816e91 100644
--- a/docs/latest/development/extensions.html
+++ b/docs/latest/development/extensions.html
@@ -115,6 +115,7 @@
 <tr><td>postgresql-metadata-storage</td><td>PostgreSQL metadata store.</td><td><a href="/docs/latest/development/extensions-core/postgresql.html">link</a></td></tr>
 <tr><td>simple-client-sslcontext</td><td>Simple SSLContext provider module to be used by Druid's internal HttpClient when talking to other Druid processes over HTTPS.</td><td><a href="/docs/latest/development/extensions-core/simple-client-sslcontext.html">link</a></td></tr>
 <tr><td>druid-pac4j</td><td>OpenID Connect authentication for druid processes.</td><td><a href="/docs/latest/development/extensions-core/druid-pac4j.html">link</a></td></tr>
+<tr><td>druid-kubernetes-extensions</td><td>Druid cluster deployment on Kubernetes without Zookeeper.</td><td><a href="/docs/latest/development/extensions-core/kubernetes.html">link</a></td></tr>
 </tbody>
 </table>
 <h2><a class="anchor" aria-hidden="true" id="community-extensions"></a><a href="#community-extensions" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Community extensions</h2>
diff --git a/docs/latest/operations/kubernetes.html b/docs/latest/operations/kubernetes.html
index 34506ce..f906d45 100644
--- a/docs/latest/operations/kubernetes.html
+++ b/docs/latest/operations/kubernetes.html
@@ -25,7 +25,7 @@
 <pre><code class="hljs">$docker pull apache/druid:<span class="hljs-number">0.16</span><span class="hljs-number">.0</span>-incubating
 </code></pre>
 <p><a href="https://github.com/druid-io/druid-operator">druid-operator</a> can be used to manage a Druid cluster on <a href="https://kubernetes.io/">Kubernetes</a> .</p>
-<p>Druid clusters deployed on Kubernetes can function without Zookeeper using <a href="/docs/latest/development/extensions-core/druid-kubernetes.html">druid–kubernetes-extensions</a> .</p>
+<p>Druid clusters deployed on Kubernetes can function without Zookeeper using <a href="/docs/latest/development/extensions-core/kubernetes.html">druid–kubernetes-extensions</a> .</p>
 </span></div></article></div><div class="docs-prevnext"></div></div></div><nav class="onPageNav"></nav></div><footer class="nav-footer druid-footer" id="footer"><div class="container"><div class="text-center"><p><a href="/technology">Technology</a> · <a href="/use-cases">Use Cases</a> · <a href="/druid-powered">Powered by Druid</a> · <a href="/docs/latest/latest">Docs</a> · <a href="/community/">Community</a> · <a href="/downloads.html">Download</a> · <a href="/faq">FAQ</a></p></div><div class="text-center"><a title="Join the user group" href="https://groups.google.com/forum/#!forum/druid-user" target="_blank"><span class="fa fa-comments"></span></a> · <a title="Follow Druid" href="https://twitter.com/druidio" target="_blank"><span class="fab fa-twitter"></span></a> · <a title="Download via Apache" href="https://www.apache.org/dyn/closer.cgi?path=/incubator/druid/{{ site.druid_versions[0].versions[0].version }}/apache-druid-{{ site.druid_versions[0].versions[0].version }}-bin.tar.gz" target="_blank"><span class="fas fa-feather"></span></a> · <a title="GitHub" href="https://github.com/apache/druid" target="_blank"><span class="fab fa-github"></span></a></div><div class="text-center license">Copyright © 2019 <a href="https://www.apache.org/" target="_blank">Apache Software Foundation</a>.<br/>Except where otherwise noted, licensed under <a rel="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA 4.0</a>.<br/>Apache Druid, Druid, and the Druid logo are either registered trademarks or trademarks of The Apache Software Foundation in the United States and other countries.</div></div></footer></div><script type="text/javascript" src="https://cdn.jsdelivr.net/docsearch.js/1/docsearch.min.js"></script><script>
                 document.addEventListener('keyup', function(e) {
                   if (e.target !== document.body) {