Adding a block model and filter mentions from blocked users (fix #60)

spec/controllers/about_controller_spec.rb

@@ -2,8 +2,8 @@ require 'rails_helper'
 
 RSpec.describe AboutController, type: :controller do
 
-  describe "GET #index" do
-    it "returns http success" do
+  describe 'GET #index' do
+    it 'returns http success' do
       get :index
       expect(response).to have_http_status(:success)
     end