app/controllers/api/v1/devices_controller.rb
class Api::V1::DevicesController < Api::BaseController
def create
device = Device.find_or_create_by!(device_id: params[:device_id])
device.update_attributes(user: current_user || nil,
registration_id: params[:registration_id],
last_actived_time: Time.current)
render json: { message: 'success' }
end
end