def index
      @customers = Customer.all

      respond_to do |format|
        format.html # index.html.erb
        format.json { render json: @customers }
      end
    end
def index
      @customers = Customer.all

      respond_to do |format|
        format.html # index.html.erb
        format.json { render json: @customers }
      end
    end
GET /customers
 GET /customers.json