title: How to sign in user when testing controllers with rspec
body: <p>I have following code</p>
  
  <pre><code>@user = FactoryGirl.create(:admin)
  post :create, company: attributes_for(:company)
  expect Company.count.should == 1
  </code></pre>
  
  <p>I can't execute post because i have authenticate user method on all controllers, how can i sign in user before that action , i am using devise.</p>