Improve translation creation form by using codemirror

app/assets/javascripts/translations.js.coffee

@@ -1,3 +1,20 @@
 # Place all the behaviors and hooks related to the matching controller here.
 # All this logic will automatically be available in application.js.
 # You can use CoffeeScript in this file: http://coffeescript.org/
+
+cm = null
+
+loadCodeMirror = ->
+  $('#translationNav li:first').addClass('active')
+  $("textarea").each ->
+    cm = CodeMirror.fromTextArea($(this).get(0), {
+      lineNumbers: false,
+      lineWrapping: true,
+      mode: "text/html"
+    })
+
+$(document).ready loadCodeMirror
+$(document).on "page:load", loadCodeMirror
+
+$(document).on "click", '#translationNav a[href="#preview"]', ->
+  $('#preview .problem-content').html(cm.getValue())