code: public void addRelationshipToTarget(final SpecTopic topic, final RelationshipType type) {
          final TargetRelationship relationship = new TargetRelationship(this, topic, type);
          topicTargetRelationships.add(relationship);
          relationships.add(relationship);
      }
docs: Add a relationship to the topic.
  
  @param topic The topic that is to be related to.
  @param type  The type of the relationship.