Changed delete to destroy when removing relation

lib/api/v3/relations/relations_api.rb

@@ -31,8 +31,7 @@ module API
           namespace ':relation_id' do
             delete do
               authorize(:manage_work_package_relations, context: @work_package.project)
-              relation = Relation.find(params[:relation_id])
+              Relation.destroy(params[:id])
-              relation.delete
               status 204
             end
           end