README.md

This part of the codebase is modified from DETR https://github.com/facebookresearch/detr under APACHE 2.0.

@article{Carion2020EndtoEndOD,
  title={End-to-End Object Detection with Transformers},
  author={Nicolas Carion and Francisco Massa and Gabriel Synnaeve and Nicolas Usunier and Alexander Kirillov and Sergey Zagoruyko},
  journal={ArXiv},
  year={2020},
  volume={abs/2005.12872}
}