Update basic-module.md

[marcorensch]

Wrote the most simple example for the new structure and gave some hints about the helper and additional Models

[robbiejackson]

Hi Marco, I appreciate the effort of contributing to the documentation but I'm actual working on the module tutorial at the moment. See pull request 261.

[marcorensch]

Hi Robbie oh... my fault, I should have checked that first...
At first glance - you really are doing a step-by-step tutorial - do you think that the two can coexist? Mine is not using mod_example.php file but the service.php which should also be pointed out...

[robbiejackson]

I haven't finished the tutorial series yet and will be including steps on the service provider file as well as on ajax and update server.

But there are lots of other documents to update for recent Joomla versions if you're keen, eg several at https://docs.joomla.org/API_Guides.

Also pull request 259 gives some help with documenting for the manual