More tests

Only one user can sign in - until this becomes multiuser

app/controllers/registrations_controller.rb

@@ -0,0 +1,17 @@
+class RegistrationsController < Devise::RegistrationsController
+
+  before_action :one_user_registered?, only: [:new, :create]
+
+  protected
+
+  def one_user_registered?
+    if User.count == 1
+      if user_signed_in?
+        redirect_to root_path
+      else
+        redirect_to new_user_session_path
+      end
+    end
+  end
+
+end