Method to deal with the callback data

find_for_oauth.rb

def self.find_for_oauth(provider_data)
    user = User.where(provider: provider_data.provider, uid: provider_data.uid).first

    unless user
      user = User.create(
        uid:      provider_data.uid,
        provider: provider_data.provider, 
        email:    provider_data.info.email,
        password: Devise.friendly_token[0, 20]
      )
    end

    user
  end