Thank you for your interest in this project.
We have no specific channel to discuss this project.
Before applying for GSoC with Sagemath, you should start getting familiar with Sagemath (how to play with graphs, do basic algorithms, etc.) and with the developer guide
http://doc.sagemath.org/html/en/developer/index.html (what’s the programing standard, how to use git, etc.). Then, you can start contributing Sagemath with smalls patchs (implementation of a new algorithm or improvement of an existing one).
David Coudert.