Rails migration to reference a User, how to add this foreign key? -

i have 2 models, user , post.

i want post model have user in i.e. add user_id in posts table.

what migration like? or manually like:

add_column :posts, :user_id:integer 

yep, manually. it'll this:

class adduseridtoposts < activerecord::migration   def self.up     add_column :posts, :user_id, :integer   end    def self.down     remove_column :posts, :user_id   end end