Adding notifications column

app/assets/javascripts/components/reducers/alerts.jsx

@@ -0,0 +1,25 @@
+import {
+  ALERT_SHOW,
+  ALERT_DISMISS,
+  ALERT_CLEAR
+} from '../actions/alerts';
+import Immutable from 'immutable';
+
+const initialState = Immutable.List([]);
+
+export default function alerts(state = initialState, action) {
+  switch(action.type) {
+    case ALERT_SHOW:
+      return state.push(Immutable.Map({
+        key: state.size > 0 ? state.last().get('key') + 1 : 0,
+        title: action.title,
+        message: action.message
+      }));
+    case ALERT_DISMISS:
+      return state.filterNot(item => item.get('key') === action.alert.key);
+    case ALERT_CLEAR:
+      return state.clear();
+    default:
+      return state;
+  }
+};