Make push follow controller and adapter style

src/Adapters/Push/ParsePushAdapter.js

@@ -7,16 +7,10 @@ const Parse = require('parse/node').Parse;
 const GCM = require('../../GCM');
 const APNS = require('../../APNS');
 
-function ParsePushAdapter() {
- this.validPushTypes = ['ios', 'android'];
- this.senders = {};
-}
+function ParsePushAdapter(pushConfig) {
+  this.validPushTypes = ['ios', 'android'];
+  this.senders = {};
 
-/**
- * Register push senders
- * @param {Object} pushConfig The push configuration which is given when parse server is initialized
- */
-ParsePushAdapter.prototype.initialize = function(pushConfig) {
   // Initialize senders
   for (let validPushType of this.validPushTypes) {
     this.senders[validPushType] = [];

src/Adapters/Push/PushAdapter.js

@@ -3,27 +3,15 @@
 // Allows you to change the push notification mechanism.
 //
 // Adapter classes must implement the following functions:
-// * initialize(pushConfig)
-// * getPushSenders(parseConfig)
-// * getValidPushTypes(parseConfig)
+// * getValidPushTypes()
 // * send(devices, installations)
 //
 // Default is ParsePushAdapter, which uses GCM for
 // android push and APNS for ios push.
+export class PushAdapter {
+  send(devices, installations) { }
 
-var ParsePushAdapter = require('./ParsePushAdapter');
-
-var adapter = new ParsePushAdapter();
-
-function setAdapter(pushAdapter) {
-  adapter = pushAdapter;
+  getValidPushTypes() { }
 }
 
-function getAdapter() {
-  return adapter;
-}
-
-module.exports = {
-  getAdapter: getAdapter,
-  setAdapter: setAdapter
-};
+export default PushAdapter;