v3: avoid N+1 queries when eager loading repository relations

lib/travis/api/v3/queries/repositories.rb

@@ -11,7 +11,9 @@ module Travis::API::V3
         all = Models::Repository
         all = all.where(active:  bool(active))  unless active.nil?
         all = all.where(private: bool(private)) unless private.nil?
-        all = all.includes(:default_branch) # TODO: use includes params
+        all = all.includes(:owner)       if includes? 'repository.owner'.freeze
+        all = all.includes(:last_build)  if includes? 'repository.last_build'.freeze
+        all = all.includes(:default_branch)
         all
       end
     end

lib/travis/api/v3/query.rb

@@ -40,6 +40,11 @@ module Travis::API::V3
       ::Sidekiq::Client.push('queue'.freeze => queue, 'class'.freeze => class_name, 'args'.freeze => args)
     end
 
+    def includes?(key)
+      @includes ||= @params['include'.freeze].to_s.split(?,.freeze)
+      @includes.include? key
+    end
+
     def bool(value)
       return false if value == 'false'.freeze
       !!value