I use Slim 3 and Eloquent ORM and play with MyBB.
I needed to create a migration from an existing database but nothing suitable found.
it is very possible that i bad looking.
search lead me to Laravel, Xethron and iseed.
All of this works fine in Laravel.
I wanted to have it all without Laravel.
what happened as a result you decide.
I suggest you RunCli - standalone command line interface.
cli used with Slim 3. today it can:
* generate migrations from existing database
* generate seeds from existing database
* create database
Also plan to add generating blank templates for controllers, models and so on.