Remove dev-boost gem

This shit was running with migrations.
Instead of using match, use resources on channels profiles

And let the resource :profiles do the trick. With path as nil,
channels/:permalink is the same, but much better (and we can use finder
method from inherited resources).
Create join table for Channels and make things simples

Now, we have a has_and_belongs_to_many association for
projects/channels and we made things simpler when renaming the
Channel::Profile model to just Channel.
Also, Fix specs and make sure everything is ok.