Require valid invitation to start sign-up process

spec/requests/signup_request_spec.rb

@@ -0,0 +1,14 @@
+require 'rails_helper'
+
+RSpec.describe "Signups", type: :request do
+
+  describe "GET /index" do
+    context "without invitation" do
+      it "returns http unauthorized" do
+        get "/signup"
+        expect(response).to have_http_status(:unauthorized)
+      end
+    end
+  end
+
+end