sessions_controller.rb

#View Original : https://github.com/plataformatec/devise/blob/master/app/controllers/devise/sessions_controller.rb
class Users::SessionsController < Devise::SessionsController
  
  respond_to :json

  # POST /resource/sign_in
  def create
    self.resource = warden.authenticate!(auth_options)
    set_flash_message(:notice, :signed_in) if is_flashing_format?
    sign_in(resource_name, resource)
    respond_with(resource) do |format|
      format.json { render json: {redirect_url: after_sign_in_path_for(resource)}, status: 200 }
    end
  end

end