refactor tags directive(tags => tag-list, tag-item) & improve search UX

src/directives/tag-item.js

@@ -0,0 +1,16 @@
+/* global angular */
+angular.module('codexen')
+  .directive('tagItem', function () {
+    return {
+      restrict: 'A',
+      template: '#<span ng-bind="tag.name"></span>',
+      scope: {
+        tag: '=tagItem'
+      },
+      link: function (scope, el) {
+        el.on('click', function () {
+          scope.$emit('tagSelected', scope.tag)
+        })
+      }
+    }
+  })