Chuan Lei

Add support to consume input schema having propertyKey's cardinality as LIST

4

According to [users_guide.md](https://github.com/IBM/janusgraph-utils/blob/master/doc/users_guide.md), the cardinality of propertyKeys can be chosen from . However, the BatchImport can only support **SINGLE**, not **LIST** nor **SET**. For example, a user in the twitter...

It would be good to explain some of the key fields in both schema.json and datamapper.json files. For example, in datamapper.json, are Left/Right in edgeMap section specific to janusgraph-utils? Or...