Add testing for Django 2.1

[adi-]

Thanx Tim

[adi-]

I try to publish it on PyPi as soon as possible.

[huangjing2016]

hello ， I tried use table by use markdownx, like ''	''
调用方式	post
参数	param+appkey

but it seems like does't work, after convert,like this:

'' | '' ---|--- 调用方式 | post 参数 | param+appkey