Add Nebula Graph to the Graph Data Model section

[jamieliu1023]

Hi there, thanks for collecting these awesome big data tools! I'd like to share with you Nebula Graph, an open-source distributed graph database, so that you may want to list it under the Graph Data Model section.

Here's a list of references for you:

1. The GitHub repo: https://github.com/vesoft-inc/nebula
2. The official website: https://nebula-graph.io

Please let me know if you need any further information. Thanks!

[oxnr]

Please create a PR.