FEATURE: Public groups.

app/assets/javascripts/discourse/controllers/group-index.js.es6

@@ -1,6 +1,6 @@
 import { popupAjaxError } from 'discourse/lib/ajax-error';
 import Group from 'discourse/models/group';
-import { observes } from 'ember-addons/ember-computed-decorators';
+import { default as computed, observes } from 'ember-addons/ember-computed-decorators';
 
 export default Ember.Controller.extend({
   queryParams: ['order', 'desc'],
@@ -17,6 +17,11 @@ export default Ember.Controller.extend({
       this.get('model').findMembers({ order: this.get('order'), desc: this.get('desc') });
   },
 
+  @computed("model.public")
+  canJoinGroup(publicGroup) {
+    return !!(this.currentUser) && publicGroup;
+  },
+
   actions: {
     removeMember(user) {
       this.get('model').removeMember(user);
@@ -29,6 +34,28 @@ export default Ember.Controller.extend({
       }
     },
 
+    joinGroup() {
+      this.set('updatingMembership', true);
+      const model = this.get('model');
+
+      model.addMembers(this.currentUser.get('username')).then(() => {
+        model.set('is_group_user', true);
+      }).catch(popupAjaxError).finally(() => {
+        this.set('updatingMembership', false);
+      });
+    },
+
+    leaveGroup() {
+      this.set('updatingMembership', true);
+      const model = this.get('model');
+
+      model.removeMember(this.currentUser).then(() => {
+        model.set('is_group_user', false);
+      }).catch(popupAjaxError).finally(() => {
+        this.set('updatingMembership', false);
+      });
+    },
+
     loadMore() {
       if (this.get("loading")) { return; }
       if (this.get("model.members.length") >= this.get("model.user_count")) { return; }