Change user and reviews serializers to serialize avatar, and adding avatar in permit params of user to update avatar image

Added trackable_type to activity serializer and fixed user.activities

Signed-off-by: Israel Barreto Sant'Anna <ibsa14@inf.ufpr.br>

See merge request !294

Fix pagination



See merge request !293

Signed-off-by: Israel Barreto Sant'Anna <ibsa14@inf.ufpr.br>

Pagination



See merge request !292

add X-Total-Count in header



See merge request !289

upgrade to rails 5



See merge request !291

Created Rating Controller, Policy and Test. Modified ReviewRatingSerializer to return rating name.

Signed-off-by: Israel Barreto Sant'Anna <ibsa14@inf.ufpr.br>

See merge request !290

Signed-off-by: Israel Barreto Sant'Anna <ibsa14@inf.ufpr.br>