lifecycle: add init hook

src/instance/init.js

@@ -90,6 +90,9 @@ exports._init = function (options) {
   // it will be filled up in _initScope().
   this._data = {}
 
+  // call init hook
+  this._callHook('init')
+
   // initialize data observation and scope inheritance.
   this._initState()
 

src/util/options.js

@@ -108,6 +108,7 @@ strats.el = function (parentVal, childVal, vm) {
  * Hooks and param attributes are merged as arrays.
  */
 
+strats.init =
 strats.created =
 strats.ready =
 strats.attached =