relation completer progress

source/core/object/relation_endpoint.cpp

@@ -17,6 +17,10 @@ relation_type relation_endpoint::type() const {
   return type_;
 }
 
+std::string relation_endpoint::type_name() const {
+  return relation_type_enum.to_string(type_);
+}
+
 const schema_node &relation_endpoint::node() const {
   return *node_;
 }