[FEATURE] `hexx model [ARGS]` added to CLI.

== Features

* `hexx model` command added to CLI.

== Addons

* CLI thor class.

== Changes

* Model generator fails if db migration is already added.

== Bugs fixed

* Generators::Model accepts string limits in {}, not ().
  hexx model item name:string{20}:uniq
Merge branch 'master' of github.com:nepalez/hexx-active_record