Add support for :any role in with_role query

[januszm]

While we have a support for :any resource, I find it useful to query for users, who have 'any' role assigned on a specific resource or class.

Here's how it can be easily done sing plain ActiveRecord:

User.joins(:roles).where(roles: { resource_type: Project }).to_a
  SELECT "users".* FROM "users" INNER JOIN "users_roles" ON "users_roles"."user_id" = "users"."id" INNER JOIN "roles" ON "roles"."id" = "users_roles"."role_id" WHERE "roles"."resource_type" = 'Project' 
=> []

# and of course, same for a resource instance

User.joins(:roles).where(roles: { resource: Project.last }).to_sql
   SELECT "users".* FROM "users" INNER JOIN "users_roles" ON "users_roles"."user_id" = "users"."id" INNER JOIN "roles" ON "roles"."id" = "users_roles"."role_id" WHERE "roles"."resource_type" = 'Project' AND "roles"."resource_id" = 'e0b45f5c-ace9-4e85-9f2e-9a132c2bed7c'"

I can prepare a PR if there's a will to addit to the gem's API

User.with_role(:any, Project)