Added sidebar menu feature

app/javascript/gabsocial/actions/sidebar.js

@@ -0,0 +1,14 @@
+export const SIDEBAR_OPEN  = 'SIDEBAR_OPEN';
+export const SIDEBAR_CLOSE = 'SIDEBAR_CLOSE';
+
+export function openSidebar() {
+  return {
+    type: SIDEBAR_OPEN,
+  };
+};
+
+export function closeSidebar() {
+  return {
+    type: SIDEBAR_CLOSE,
+  };
+};