** Create a new command

This command works like phinx status, but with a difference, it print on the screen a json object like this:

[
{"status": "up/down", "migration_id": "", "migration_name" : ""},
{"status": "up/down", "migration_id": "", "migration_name" : ""}
]

Motivation to do this: Sometime u execute phinx in a CI tool or in a Deploy script and with the default output it´s hard to get the list of migrations.