Adding detailed documentation of the markdown syntax.

This includes standard markdown as well as GitLab extended markdown as well as references to documents used.

app/views/help/markdown.html.haml

@@ -2,126 +2,6 @@
   %h3.page_title GitLab Flavored Markdown
   %br
 
-  .row
-    .span8
-      %p
-        For GitLab we developed something we call "GitLab Flavored Markdown" (GFM).
-        It extends the standard Markdown in a few significant ways adds some useful functionality.
-
-      %p You can use GFM in:
-      %ul
-        %li commit messages
-        %li comments
-        %li wall posts
-        %li issues
-        %li merge requests
-        %li milestones
-        %li wiki pages
-
-    .span4
-      .alert.alert-info
-        %p
-          If you're not already familiar with Markdown, you should spend 15 minutes and go over the excellent
-          %strong= link_to "Markdown Syntax Guide", "http://daringfireball.net/projects/markdown/syntax"
-          at Daring Fireball.
-
-  .row
-    .span8
-      %h3 Differences from traditional Markdown
-
-      %h4 Newlines
-
-      %p
-        The biggest difference that GFM introduces is in the handling of linebreaks.
-        With traditional Markdown you can hard wrap paragraphs of text and they will be combined into a single paragraph. We find this to be the cause of a huge number of unintentional formatting errors.
-        GFM treats newlines in paragraph-like content as real line breaks, which is probably what you intended.
-
-
-      %p The next paragraph contains two phrases separated by a single newline character:
-      %pre= "Roses are red\nViolets are blue"
-      %p becomes
-      = markdown "Roses are red\nViolets are blue"
-
-      %h4 Multiple underscores in words
-
-      %p
-        It is not reasonable to italicize just <em>part</em> of a word, especially when you're dealing with code and names often appear with multiple underscores.
-        Therefore, GFM ignores multiple underscores in words.
-
-      %pre= "perform_complicated_task\ndo_this_and_do_that_and_another_thing"
-      %p becomes
-      = markdown "perform_complicated_task\ndo_this_and_do_that_and_another_thing"
-
-      %h4 URL autolinking
-
-      %p
-        GFM will autolink standard URLs you copy and paste into your text.
-        So if you want to link to a URL (instead of a textual link), you can simply put the URL in verbatim and it will be turned into a link to that URL.
-
-      %h4 Fenced code blocks
-
-      %p
-        Markdown converts text with four spaces at the front of each line to code blocks.
-        GFM supports that, but we also support fenced blocks.
-        Just wrap your code blocks in <code>```</code> and you won't need to indent manually to trigger a code block.
-
-      %pre= %Q{```ruby\nrequire 'redcarpet'\nmarkdown = Redcarpet.new("Hello World!")\nputs markdown.to_html\n```}
-      %p becomes
-      = markdown %Q{```ruby\nrequire 'redcarpet'\nmarkdown = Redcarpet.new("Hello World!")\nputs markdown.to_html\n```}
-
-      %h4 Emoji
-
-  .row
-    .span8
-      :ruby
-        puts markdown %Q{Sometimes you want to be :cool: and add some :sparkles: to your :speech_balloon:. Well we have a :gift: for you:
-
-          :exclamation: You can use emoji anywhere GFM is supported. :sunglasses:
-
-          You can use it to point out a :bug: or warn about :monkey:patches. And if someone improves your really :snail: code, send them a :bouquet: or some :candy:. People will :heart: you for that.
-
-          If you are :new: to this, don't be :fearful:. You can easily join the emoji :circus_tent:. All you need to do is to :book: up on the supported codes.
-          }
-
-    .span4
-      .alert.alert-info
-        %p
-          Consult the
-          %strong= link_to "Emoji Cheat Sheet", "http://www.emoji-cheat-sheet.com/"
-          for a list of all supported emoji codes.
-
-  .row
-    .span8
-      %h4 Special GitLab references
-
-      %p
-        GFM recognizes special references.
-        You can easily reference e.g. a team member, an issue or a commit within a project.
-        GFM will turn that reference into a link so you can navigate between them easily.
-
-      %p GFM will recognize the following references:
-      %ul
-        %li
-          %code @foo
-          for team members
-        %li
-          %code #123
-          for issues
-        %li
-          %code !123
-          for merge request
-        %li
-          %code $123
-          for snippets
-        %li
-          %code 1234567
-          for commits
-
-      -# this example will only be shown if the user has a project with at least one issue
-      - if @project = current_user.authorized_projects.first
-        - if issue = @project.issues.first
-          %p For example in your #{link_to @project.name, project_path(@project)} project, writing:
-          %pre= "This is related to ##{issue.id}. @#{current_user.username} is working on solving it."
-          %p becomes:
-          = markdown "This is related to ##{issue.id}. @#{current_user.username} is working on solving it."
-        - @project = nil # Prevent this from bubbling up to page title
+  .help_body
+    = preserve do
+      = markdown File.read(Rails.root.join("doc", "markdown", "markdown.md"))