Remove unnecessary braces

Signed-off-by: David Celis <me@davidcel.is>
Code re-organization

Signed-off-by: David Celis <me@davidcel.is>
Switch to the expectation syntax

Signed-off-by: David Celis <me@davidcel.is>
Add support for Grape

Signed-off-by: David Celis <me@davidcel.is>
Extract shared code

Signed-off-by: David Celis <me@davidcel.is>
Extract shared spec tests

Signed-off-by: David Celis <me@davidcel.is>
Test against both the will_paginate and the kaminari logic

Signed-off-by: David Celis <me@davidcel.is>