Update Gemfile source to https
diff --git a/site/Gemfile b/site/Gemfile
index 01cb75f..469a8e7 100644
--- a/site/Gemfile
+++ b/site/Gemfile
@@ -15,7 +15,7 @@
 # specific language governing permissions and limitations
 # under the License.
 
-source 'http://rubygems.org'
+source 'https://rubygems.org'
 
 gem "middleman"
 
diff --git a/site/Gemfile.lock b/site/Gemfile.lock
index aa559ce..d86cda3 100644
--- a/site/Gemfile.lock
+++ b/site/Gemfile.lock
@@ -1,5 +1,5 @@
 GEM
-  remote: http://rubygems.org/
+  remote: https://rubygems.org/
   specs:
     activesupport (4.2.4)
       i18n (~> 0.7)