FIX: tag search should not be case sensitive

app/assets/javascripts/discourse/components/tag-chooser.js.es6

@@ -77,7 +77,7 @@ export default Ember.TextField.extend({
         callback(data);
       },
       createSearchChoice: function(term, data) {
-        term = term.replace(filterRegexp, '').trim();
+        term = term.replace(filterRegexp, '').trim().toLowerCase();
 
         // No empty terms, make sure the user has permission to create the tag
         if (!term.length || !self.get('allowCreate') || self.get('termMatchesForbidden')) return;

lib/discourse_tagging.rb

@@ -56,6 +56,7 @@ module DiscourseTagging
   def self.filter_allowed_tags(query, guardian, opts={})
     term = opts[:term]
     if term.present?
+      term.downcase!
       term.gsub!(/[^a-z0-9\.\-\_]*/, '')
       term.gsub!("_", "\\_")
       query = query.where('tags.name like ?', "%#{term}%")