ActiveRecord Direct Inheritance :: Migration Not Supported

Question

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

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

Everyone on the Internet says you just need to change

class CreateRelationships < ActiveRecord::Migration

to

class CreateRelationships < ActiveRecord::Migration[4.2]

The problem is that this solution does not work for me. Thank you in advance!

Answer 1

Add [5.1] if your version of ruby ​​rails [5.1.5] even ... just 5.1 class CreateRelationships <ActiveRecord :: Migration [5,1]

. gemfile , , .

, , , . , , ..

,