* Add the ability to create restful API controllers
* Update the model.json template file
* Modify the 'create controller' command of the drogon_ctl
* access column values by column array indexes instead of column names when constructing an instance of a model class
* Fix a bug of mysql database
* Add some static SQL into models
* Add validations to models
* Add setToNull method to models
* Support 'where in' substatement
* Delay rendering from json to the response body. This allows users to modify the json object before sending a response.
* Add synchronous method to the HttpClient class
