app/models/user.rb
class User < ActiveRecord::Base
# Include default devise modules. Others available are:
# :confirmable, :lockable, :timeoutable and :omniauthable
devise :database_authenticatable, :registerable,
:recoverable, :rememberable, :trackable, :validatable
has_many :shelters, through: :pets
has_many :favorite_pets
has_many :pets, through: :favorite_pets
validates_presence_of :name
#has_many :favoritepets
end