Merge branch 'update-rugments' into 'master'

Update rugments to 1.0.0.beta6 to fix C# highlighting.

Fixes #1259.

See merge request !435

Gemfile.lock

@@ -516,7 +516,7 @@ GEM
     rubyntlm (0.5.0)
     rubypants (0.2.0)
     rugged (0.21.4)
-    rugments (1.0.0.beta5)
+    rugments (1.0.0.beta6)
     safe_yaml (0.9.7)
     sanitize (2.1.0)
       nokogiri (>= 1.4.4)