Modify jquery.tagsinput plugin to allow filtering tags, and filter tags by…

Modify jquery.tagsinput plugin to allow filtering tags, and filter tags by converting them to lowercase so the service doesn't just error when you submit.

lms/static/coffee/src/discussion/utils.coffee

@@ -107,6 +107,9 @@ class @DiscussionUtil
       [event, selector] = eventSelector.split(' ')
       $local(selector).unbind(event)[event] handler
 
+  @processTag: (text) ->
+    text.toLowerCase()
+
   @tagsInputOptions: ->
     autocomplete_url: @urlFor('tags_autocomplete')
     autocomplete:
@@ -116,6 +119,7 @@ class @DiscussionUtil
     width: '100%'
     defaultText: "Tag your post: press enter after each tag"
     removeWithBackspace: true
+    preprocessTag: @processTag
 
   @formErrorHandler: (errorsField) ->
     (xhr, textStatus, error) ->

lms/static/js/jquery.tagsinput.js

@@ -85,6 +85,11 @@
 
 				value = jQuery.trim(value);
 
+				if (options.callback && tags_callbacks[id] && tags_callbacks[id]['preprocessTag']) {
+					var f = tags_callbacks[id]['preprocessTag'];
+					value = f.call(this, value);
+				}
+
 				if (options.unique) {
 					var skipTag = $(this).tagExist(value);
 					if(skipTag == true) {
@@ -211,11 +216,12 @@
 
 			delimiter[id] = data.delimiter;
 
-			if (settings.onAddTag || settings.onRemoveTag || settings.onChange) {
+			if (settings.onAddTag || settings.onRemoveTag || settings.onChange || settings.preprocessTag) {
 				tags_callbacks[id] = new Array();
 				tags_callbacks[id]['onAddTag'] = settings.onAddTag;
 				tags_callbacks[id]['onRemoveTag'] = settings.onRemoveTag;
 				tags_callbacks[id]['onChange'] = settings.onChange;
+				tags_callbacks[id]['preprocessTag'] = settings.preprocessTag;
 			}
 
 			var markup = '<div id="'+id+'_tagsinput" class="tagsinput"><div id="'+id+'_addTag">';