I'm getting problem with csv. When I use below code in my Controller method then it works but when I put this in my migration then this don't work. Why so
Put in some debug to work out what is going wrong. Is it executing self.up? Is it finding the file? Does it find any rows? Does the save fail (it might be worth testing this first by checking the return from save, perhaps validations are failing).
Have a look at the Rails Guide on Debugging for debugging techniques. Knowing how to debug is one of the most important skills, in five minutes debugging you can save the time spent asking questions and waiting hours for help.
Colin