Ember addon not working after linking ember-cli with local clone

This is what I did:

git clone http://ift.tt/2xQXtlo
cd ember-cli
npm link

Then:

cd ..
ember new mytestproject
cd mytestproject
npm link ember-cli
ember addon my-addon

I get this error:

You cannot use the addon command inside an ember-cli project.

I can run other commands such as ember serve, ember g route ...

Any advices?