[feature] implementing model generation for resources

[paganotoni]

This adds model/migration generation for the resources generator, its related with #42

[markbates]

Sorry about the delay, I just got around to playing with this. A few observations.

• There's no documentation when using --help anywhere that explains this. so it might not be obvious that this will create a model as well.
• model generator has an option to --skip-migration, which this doesn't support
• there's no way to not generate a model.

[paganotoni]

Thanks @markbates I'll work on these and let you know, thanks for the feedback.

[markbates]

You should also look at this PR #272

[paganotoni]

@markbates added examples on command and allowed users to --skip-migration or --skip-model which will skip both, model and migration.

[markbates]

Looks like the --skip-migration flag doesn't work. :(

buffalo g resource bands --skip-migration
Buffalo version 0.7.4

--> actions/bands.go
--> actions/bands_test.go
--> buffalo db g model band
v3.11.6

--> models/band.go
--> models/band_test.go
--> goimports -w .
> migrations/20170308230324_create_bands.up.fizz
> migrations/20170308230324_create_bands.down.fizz
--> goimports -w .

[paganotoni]

^ This needs some changes on filetest. (PR's ready)

[markbates]

@apaganobeleno i merged the filetest changes if you want to rebase this and see if the tests pass.

[paganotoni]

@markbates all set, thanks for merging those