Improve @mention regex

spec/controllers/tags_controller_spec.rb

@@ -3,6 +3,10 @@ require 'rails_helper'
 RSpec.describe TagsController, type: :controller do
 
   describe 'GET #show' do
+    before do
+      Fabricate(:tag, name: 'test')
+    end
+
     it 'returns http success' do
       get :show, params: { id: 'test' }
       expect(response).to have_http_status(:success)