gitlabhq/app/views/tree/edit.html.haml

.file-editor
  .file_name
    File: 
  %span.file_name
    = @tree.path.force_encoding('utf-8')
    %br
    = form_tag(project_tree_path(@project, @id), :method => :put) do
      #editor
        = @tree.data
      = hidden_field_tag 'last_commit', @last_commit
      = hidden_field_tag 'content'
      
      = text_area_tag 'text_commit'
      = submit_tag "Save"

:javascript
  var editor = ace.edit("editor");
  editor.setTheme("ace/theme/twilight");
  editor.getSession().setMode("ace/mode/javascript");