Support direct access server option (#5550)

* Support direct access config

test options

* add test

* fix test

* fix definitions

* improve docs

* Update .travis.yml

* Revert "Update .travis.yml"

This reverts commit 407f1384953b64bad9e63068db8564c3584ca3a4.

src/ParseServer.js

@@ -136,7 +136,7 @@ class ParseServer {
    * @static
    * Create an express app for the parse server
    * @param {Object} options let you specify the maxUploadSize when creating the express app  */
-  static app({ maxUploadSize = '20mb', appId }) {
+  static app({ maxUploadSize = '20mb', appId, directAccess }) {
     // This app serves the Parse API directly.
     // It's the equivalent of https://api.parse.com/1 in the hosted Parse API.
     var api = express();
@@ -193,7 +193,10 @@ class ParseServer {
         ParseServer.verifyServerUrl();
       });
     }
-    if (process.env.PARSE_SERVER_ENABLE_EXPERIMENTAL_DIRECT_ACCESS === '1') {
+    if (
+      process.env.PARSE_SERVER_ENABLE_EXPERIMENTAL_DIRECT_ACCESS === '1' ||
+      directAccess
+    ) {
       Parse.CoreManager.setRESTController(
         ParseServerRESTController(appId, appRouter)
       );