has_many, belongs_to relation in active record migration rails 4

Question

I have a User model and a Task model. I have not mentioned any relation between them while creating them.

I need to establish that U

Answer 1

The Relationship in Rails is taken care by model not by Rails.

So you just need to define this relationship in your model:

class User < ActiveRecord::Base
  has_many :tasks
end

class Task < ActiveRecord::Base
  belongs_to :user
end

And just make sure that a user_id field is present in the migration for creating the "tasks" table.