add liked collections test

spec/acceptance/users_spec.rb

@@ -156,6 +156,21 @@ resource 'Users' do
     end
   end
 
+  get '/v1/users/:id/collections/liked' do
+    include_context "authenticate_user"
+
+    before do
+      create(:like, user: @user, likeable: create(:collection))
+    end
+
+    let(:id) { @user.id }
+
+    example 'Showing a user’s liked collections' do
+      do_request
+      expect(status).to eq(200)
+    end
+  end
+
   get '/v1/users/:id/learning_objects/liked' do
     include_context "authenticate_user"