I was playing around with Rails admin and I noticed something.
Attributes which are defined as below in model, counted as "Required" in Rails admin
validates :user, presence: true
t.datetime "created_at",:null => false
:null => false means that this is a database restriction, i.e. under no circumstance will the database allow a null value.
presence: true is a model level validation so will take place before the object is inserted into the database. There may be a case you want to break these validations (for example edge cases or in your specs) You can then skip validation using
:validates => false and the object will still go into the database, with a null DB restriction, this won't happen.