OGM-547 Add test for unique constraints in Neo4j
OGM-547 Add test for skipping unique constraints generation
OGM-547 Update javadoc
OGM-547 Better logging during the creation of unique constraints in Neo4j
OGM-547 Avoid the creation of unique constraints on foreign key columns

  Neo4j does not create properties for foreign key columns, so we don't
  need to create a constraint for them