app/models/user.rb
class User
include Mongoid::Document
include Mongoid::Timestamps
devise :database_authenticatable, :registerable,
:recoverable, :rememberable, :trackable, :validatable
## Database authenticatable
field :email, :type => String, :default => ""
field :encrypted_password, :type => String, :default => ""
## Recoverable
field :reset_password_token, :type => String
field :reset_password_sent_at, :type => Time
## Rememberable
field :remember_created_at, :type => Time
## Trackable
field :sign_in_count, :type => Integer, :default => 0
field :current_sign_in_at, :type => Time
field :last_sign_in_at, :type => Time
field :current_sign_in_ip, :type => String
field :last_sign_in_ip, :type => String
field :name
field :github_account
validates_presence_of :email
validates_presence_of :encrypted_password
validates_presence_of :name
index({ created_at: 1 })
end