Move alerts to their own controller

ember/app/controllers/alerts.js

@@ -0,0 +1,17 @@
+import Ember from 'ember';
+
+export default Ember.Controller.extend({
+	alerts: [],
+
+	actions: {
+		alert: function(message) {
+			this.get('alerts').pushObject(message);
+		},
+		dismissAlert: function(message) {
+			this.get('alerts').removeObject(message);
+		},
+		clearAlerts: function() {
+			this.get('alerts').clear();
+		}
+	}
+});