Merge branch 'fix_markup_encoding' into 'master'

Fix encoding of output of markup, prevent 500 for non-ascii characters

#### What does this MR do?

This MR forces the output of `Github::markup` to have the same encoding as the input to it.

#### Why was this MR needed?

This prevents 500 errors if the markup contains non-asci characters.

#### What are the relevant issue numbers / Feature requests?

This MR closes

* #296
* https://github.com/gitlabhq/gitlabhq/issues/7023

/cc @jacobvosmaer

See merge request !160

app/helpers/application_helper.rb

@@ -221,7 +221,8 @@ module ApplicationHelper
   end
 
   def render_markup(file_name, file_content)
-    GitHub::Markup.render(file_name, file_content).html_safe
+    GitHub::Markup.render(file_name, file_content).
+      force_encoding(file_content.encoding).html_safe
   rescue RuntimeError
     simple_format(file_content)
   end

spec/helpers/application_helper_spec.rb

@@ -217,4 +217,13 @@ describe ApplicationHelper do
       ).to eq("<a href=\"http://www.example.com\" rel=\"noreferrer nofollow\">Example</a>")
     end
   end
+
+  describe 'markup_render' do
+    let(:content) { 'Noël' }
+
+    it 'should preserve encoding' do
+      content.encoding.name.should == 'UTF-8'
+      expect(render_markup('foo.rst', content).encoding.name).to eq('UTF-8')
+    end
+  end
 end