Directly inheriting from ActiveRecord::Migration is not supported

Question

I just finished my first Ruby on Rails app, and I'm trying to deploy it to Heroku. I am now at the final step, but when I run the following command (heroku run rake db:migrate), I am getting this error :

StandardError : Directly inheriting from ActiveRecord::Migration is not supported. 
Please specify the Rails release the migration was written for.

Everyone on the web is saying that you just have to change

class CreateRelationships < ActiveRecord::Migration

to

class CreateRelationships < ActiveRecord::Migration[4.2]

The problem is that this solution doesn't work for me. Thank you in advance!

Answer 1

Add [5.1] if your ruby rails version is [5.1.5] even...just 5.1 class CreateRelationships < ActiveRecord::Migration[5.1]

like in this thread. Check in gemfile at the very top to see what version of rails you have.

I ran bundle install straight afters and and I ran the command that originally showed this error and it worked then worked. Not sure you need to run bundle install though..

Hope this helps Sput