Refactored class_diagram generator to common base class template

src/common/model/relationship.cc

@@ -20,34 +20,6 @@
 
 namespace clanguml::common::model {
 
-std::string to_string(relationship_t r)
-{
-    switch (r) {
-    case relationship_t::kNone:
-        return "none";
-    case relationship_t::kExtension:
-        return "extension";
-    case relationship_t::kComposition:
-        return "composition";
-    case relationship_t::kAggregation:
-        return "aggregation";
-    case relationship_t::kContainment:
-        return "containment";
-    case relationship_t::kOwnership:
-        return "ownership";
-    case relationship_t::kAssociation:
-        return "association";
-    case relationship_t::kInstantiation:
-        return "instantiation";
-    case relationship_t::kFriendship:
-        return "frendship";
-    case relationship_t::kDependency:
-        return "dependency";
-    default:
-        return "invalid";
-    }
-}
-
 relationship::relationship(relationship_t type, const std::string &destination,
     scope_t scope, const std::string &label,
     const std::string &multiplicity_source,