Require account registrar to be present

#475

app/models/account.rb

@@ -1,6 +1,7 @@
 class Account < ActiveRecord::Base
   include Versions
-  belongs_to :registrar
+
+  belongs_to :registrar, required: true
   has_many :account_activities
 
   validates :account_type, presence: true

spec/models/account_spec.rb

@@ -1,6 +1,6 @@
 require 'rails_helper'
 
-describe Account do
+RSpec.describe Account do
   context 'with invalid attribute' do
     before :all do
       @account = Account.new
@@ -45,4 +45,14 @@ describe Account do
       end
     end
   end
+
+  describe 'registrar validation', db: false do
+    subject(:account) { described_class.new }
+
+    it 'rejects absent' do
+      account.registrar = nil
+      account.validate
+      expect(account.errors).to have_key(:registrar)
+    end
+  end
 end