Add test file

test-server/.gitignore

 uploads/*
 public/*
 !public/github.png
+!public/22mb-dummy
 !uploads/readme

test-server/server.js

 var JS_SOURCE_PATH = '../test/',
     APP_SOURCE_PATH = '../RNFetchBlobTest/';
 
+// watch index.js in src folder
 chokidar
   .watch('../src/index.js')
   .on('change', function(path) {
     });
   })
 
+// watch files in  test folder
 chokidar
   .watch(JS_SOURCE_PATH)
   .on('add', function(path) {