user from omniauth

  def self.from_omniauth(auth, opts = {})
    where('(provider = :provider AND uid = :uid) OR email = :email',
            provider: auth.provider,
            uid: auth.uid,
            email: auth.info.email).first_or_initialize.tap do |user|

      user.provider = auth.provider
      user.uid = auth.uid

      user.oauth_token = auth.credentials.token
      user.refresh_token = auth.credentials.refresh_token unless auth.credentials.refresh_token.blank?

      user.email = auth.info.email
      user.password = Devise.friendly_token[0,20] unless user.persisted?
      user.firstname = auth.info.first_name
      user.lastname = auth.info.last_name
      user.save!
    end
  end