Introduce recent to Follow (#3247)

Introduce recent to Follow, as Account and other models have.
This change also adds specs for the scope and the dependents.

spec/controllers/follower_accounts_controller_spec.rb

@@ -4,11 +4,21 @@ describe FollowerAccountsController do
   render_views
 
   let(:alice) { Fabricate(:account, username: 'alice') }
+  let(:follower0) { Fabricate(:account) }
+  let(:follower1) { Fabricate(:account) }
 
   describe 'GET #index' do
-    it 'returns http success' do
+    it 'assigns follows' do
+      follow0 = follower0.follow!(alice)
+      follow1 = follower1.follow!(alice)
+
       get :index, params: { account_username: alice.username }
 
+      assigned = assigns(:follows).to_a
+      expect(assigned.size).to eq 2
+      expect(assigned[0]).to eq follow1
+      expect(assigned[1]).to eq follow0
+
       expect(response).to have_http_status(:success)
     end
   end