Simple OAuth authorisation with multiply providers

auth_service.rb

class AuthService
  def self.authorize(auth_data)
    provider = Provider.find_or_create_by(name: auth_data['name'], uid: auth_data['uid'])

    if provider.user.present?
      provider.user
    else
      user = User.find_or_create_with_oauth(auth_data['info'])
      provider.update(user: user)
      user
    end
  end
end

provider.rb

class Provider < ActiveRecord::Base
  validates_presence_of :uid, :name
  validates_uniqueness_of :uid, scope: :name

  belongs_to :user, dependent: :destroy
end

session_controller.rb

class SessionController < ApplicationController
  def create
    self.current_user = AuthService.authorize(safe_params)
    render json: current_user
  end

  def destroy
    self.current_user = nil
    render json: { success: true }
  end

  private

  def safe_params
    params.require(:data).permit!
  end
end

user.rb

class User < ActiveRecord::Base
  validates :name, presence: true
  validates :email, presence: true, uniqueness: true

  has_many :providers

  def self.find_or_create_with_oauth(info)
    cond = { email: info['email'] }
    if User.where(cond).exists?
      where(cond).first
    else
      create(cond.merge(name: info['name']))
    end
  end
end