Address the models/resources -> routes debacle

[adrianthedev]

There's confusion in Avo regarding resource generation.

Scenario:

We use the pay gem and want to show the subscriptions inside Avo.

We start by generating a resource r g avo:resource subscription. Next, we have to change the model_class to Pay::Subscription. Now we notice that the path generated for that resource is /avo/resources/pay_subscriptions.

Notice the pay_subscriptions. We might expect it to be subscriptions. SubscriptionResource turns to subscription not pay_subscriptions. Next we'll notice that the generated controller for that resource SubscriptionsController does not work. We have to manually change it to PaySubscriptionsController for it to work.
That's because we went from the assumption that the routes should be generated based on the model, and not the resource.

Cons

That's bad (as @yrashk mentioned) because if we'd like to use multiple resources for the same model, that wouldn't really work out of the box.

We're open to suggestions on if we should or shouldn't move the routing from the model to the resource.