Merge branch 'footnotes-markdown' into 'master'

Add footnotes support to Markdown

This merge request fix this issue : https://gitlab.com/gitlab-org/gitlab-ce/issues/555

See merge request !572

CHANGELOG

@@ -29,6 +29,7 @@ v 7.11.0 (unreleased)
   - Improve UI for mobile phones on dashboard and project pages
   - Add room notification and message color option for HipChat
   - Allow to use non-ASCII letters and dashes in project and namespace name. (Jakub Jirutka)
+  - Add footnotes support to Markdown (Guillaume Delbergue)
 
 v 7.10.0
   - Ignore submodules that are defined in .gitmodules but are checked in as directories.

app/helpers/gitlab_markdown_helper.rb

@@ -49,7 +49,8 @@ module GitlabMarkdownHelper
         strikethrough:       true,
         lax_spacing:         true,
         space_after_headers: true,
-        superscript:         true
+        superscript:         true,
+        footnotes:           true
       )
     end