使用rake db：migrate命令和mysql在Rails中创建表的PRIMARY KEY问题

My version of rails is 4.0.0, my version of mysql is Ver 14.14 Distrib 5.7.9, for Win64 (x86_64). I am operating of an older version of rails as I was getting some clashes with the mysql as per my previous question My version of rails is 4.0.0, my version of mys