Add model spec for SpamLog

spec/models/spam_log_spec.rb

+require 'spec_helper'
+
+describe SpamLog, models: true do
+  describe 'associations' do
+    it { is_expected.to belong_to(:user) }
+  end
+
+  describe 'validations' do
+    it { is_expected.to validate_presence_of(:user) }
+  end
+end