Add specs for User#is_admin?

spec/factories/devise.rb

@@ -0,0 +1,8 @@
+FactoryBot.define do
+  factory :user do
+    id { 1 }
+    cn { "jimmy" }
+    email { "jimmy@example.com" }
+    password { "dis-muh-password" }
+  end
+end