README.md in alipay-0.6.0.beta2 vs README.md in alipay-0.6.0.beta3

- old
+ new

@@ -9,11 +9,11 @@
 ## Installation
 
 Add this line to your application's Gemfile:
 
 ```ruby
-gem 'alipay', '~> 0.6.0.beta2'
+gem 'alipay', '~> 0.6.0.beta3'
 ```
 
 or master branch:
 
 ```ruby
@@ -349,11 +349,11 @@
   out_return_no: '20150401000-0001',
   out_trade_no: '201504010000001',
   return_amount: '10.00',
   currency: 'USD',
   reason: 'Reason',
-  gmt_return: '2015-04-01 00:00:00'
+  gmt_return: '20150401000000'
 )
 ```
 
 #### ARGUMENTS
 
@@ -362,10 +362,12 @@
 | out_return_no | required | Refund no, you should store it to db to avoid alipay duplicate refund. |
 | out_trade_no | required | Order number in your application. |
 | return_amount | required | Refund amount. |
 | currency | required | Abbreviated currency name. |
 | reason | required | Refun reason. |
-| notify_url | optional | Alipay asyn notify url. |
+| gmt_return | required * | YYYYMMDDHHMMSS Beijing Time. |
+
+\* Auto set Time.now if not set.
 
 ### 验证通知
 
 #### Name
 