Employer registration
Your setup is going to eventually be working around Rails configurations, which are built for the canonical index, new, create, show, edit, update, delete.

Rails does resource routing for this very reason (read more in the Rails Guide on Routing). It's also very in-line with HTTP verb standards and will make turning this into a JSON API trivial, should you need one.

Since your Employer and Employee are separate domain objects, I would make them separate controllers. This leaves some nice future options for other actions when you need them like edit and destroy.

class EmployerController &lt; ApplicationController
  def new
    @employer_signup = EmployerSignup.new
  end

  def create
    @employer_signup = EmployerSignup.new(params[:employer_signup])

    if @employer_signup.save
      sign_in @employer_signup.user
      redirect_to root_path, notice: 'You signed up successfully.'
    else
      render action: :employer_registration
    end
  end
end

class EmployeeController &lt; ApplicationController
  def new
    @employee_signup = EmployeeSignup.new
  end

  def create
    @employee_signup = EmployeeSignup.new(params[:employee_signup])

    if @employee_signup.save
      sign_in @employee_signup.user
      redirect_to root_path, notice: 'You signed up successfully'
    else
      render action: :employee_registration
    end
  end
end