test: add tests for Server model

spec/factories/organization_factory.rb

@@ -28,5 +28,10 @@ FactoryBot.define do
     name { "Acme Inc" }
     sequence(:permalink) { |n| "org#{n}" }
     association :owner, factory: :user
+
+    trait :suspended do
+      suspended_at { 1.day.ago }
+      suspension_reason { "test" }
+    end
   end
 end