code: public static Map<String, CollectionMetaData> builder(JsonDBConfig dbConfig) {
      Map<String, CollectionMetaData> collectionMetaData = new LinkedHashMap<String, CollectionMetaData>();
      Reflections reflections = new Reflections(dbConfig.getBaseScanPackage());
      Set<Class<?>> docClasses = reflections.getTypesAnnotatedWith(Document.class);
      for(Class<?> c : docClasses) {
        Document d = c.getAnnotation(Document.class);
        String collectionName = d.collection();
        String version = d.schemaVersion();
        CollectionMetaData cmd = new CollectionMetaData(collectionName, c, version, dbConfig.getSchemaComparator());
        collectionMetaData.put(collectionName, cmd);
      }
      return collectionMetaData;
    }
docs: A utility builder method to scan through the specified package and find all classes/POJOs
  that are annotated with the @Document annotation.
  
  @param dbConfig the object that holds all the baseScanPackage and other settings.
  @return A Map of collection classes/POJOs