This really should use ActiveRecords associations and not something selfmade. make sure there are the columns `user_id` and `post_id` on this table, add a `belongs_to :user` and `belongs_to :post` here and a `has_many :post_reporters` to the User mode. While at it I think just `PostReport` would give a nicer name.

Also make sure to add some [validations](http://guides.rubyonrails.org/active_record_validations.html)