Document useModel() Method.

[TerryKern]

I am using:

CakePHP version: 3.10.4
Crud version 5.5.1

I was attempting to use the CRUD plugin on a table from within in a plugin. I had to manually search the code until I found the useModel() method. I knew that I had to specify that my table was in a plugin, however, since this method wasn't mentioned I spent quite some time searching for it. Would be nice to mention useModel() in the docs.