Upgrade all gems to the current version
diff --git a/Gemfile.lock b/Gemfile.lock
index 83f41f6..da0ff91 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    addressable (2.5.0)
+    addressable (2.5.1)
       public_suffix (~> 2.0, >= 2.0.2)
     colorator (1.1.0)
     ffi (1.9.18)
@@ -22,7 +22,7 @@
       jekyll (~> 3.3)
     jekyll-sass-converter (1.5.0)
       sass (~> 3.4)
-    jekyll-sitemap (1.0.0)
+    jekyll-sitemap (1.1.1)
       jekyll (~> 3.3)
     jekyll-watch (1.5.0)
       listen (~> 3.0, < 3.1)
@@ -40,7 +40,12 @@
       ffi (>= 0.5.0)
     rouge (1.11.1)
     safe_yaml (1.0.4)
-    sass (3.4.23)
+    sass (3.4.24)
+    thread_safe (0.3.6)
+    tzinfo (1.2.3)
+      thread_safe (~> 0.1)
+    tzinfo-data (1.2017.2)
+      tzinfo (>= 1.0.0)
 
 PLATFORMS
   ruby
diff --git a/_config.yml b/_config.yml
index aaf735f..6da7b3d 100644
--- a/_config.yml
+++ b/_config.yml
@@ -21,6 +21,7 @@
 exclude:
   - Gemfile
   - Gemfile.lock
+  - README.txt
 
 markdown: kramdown
 kramdown: