【LightGCN】 Reproduction in PaddlePaddle with PGL

[Huang Zhengjie]

Great paper for recommender systems. Here is our reproduction of LightGCN and NGCF.

https://github.com/PaddlePaddle/PGL/tree/main/examples/lightgcn

https://github.com/PaddlePaddle/PGL/tree/main/examples/ngcf