Default follows for new users (#4871)

When a new user confirms their e-mail, bootstrap their home timeline
by automatically following a set of accounts. By default, all local
admin accounts (that are unlocked). Can be customized by new admin
setting (comma-separated usernames, local and unlocked only)

spec/controllers/auth/confirmations_controller_spec.rb

@@ -10,4 +10,22 @@ describe Auth::ConfirmationsController, type: :controller do
       expect(response).to have_http_status(:success)
     end
   end
+
+  describe 'GET #show' do
+    let!(:user) { Fabricate(:user, confirmation_token: 'foobar', confirmed_at: nil) }
+
+    before do
+      allow(BootstrapTimelineWorker).to receive(:perform_async)
+      @request.env['devise.mapping'] = Devise.mappings[:user]
+      get :show, params: { confirmation_token: 'foobar' }
+    end
+
+    it 'redirects to login' do
+      expect(response).to redirect_to(new_user_session_path)
+    end
+
+    it 'queues up bootstrapping of home timeline' do
+      expect(BootstrapTimelineWorker).to have_received(:perform_async).with(user.account_id)
+    end
+  end
 end