rn-79: add GSoC 2021 article

Author: chriscool

_posts/2021-09-30-edition-79.markdown

@@ -17,9 +17,24 @@ This edition covers what happened during the month of August 2021.
 
 ## Discussions
 
-<!---
 ### General
--->
+
+*[GSoC (Google Summer of Code) 2021 End](https://summerofcode.withgoogle.com/organizations/5908380398387200/#projects)
+
+ Congratulations to the two students who had been accepted to work on
+ Git as part of the [GSoC 2021](https://summerofcode.withgoogle.com/)
+ as they successfully passed all the evaluations!
+
+- Atharva Raykar worked on the
+[Finish converting submodule to builtin](https://summerofcode.withgoogle.com/projects/#4754589292691456)
+ project. He was co-mentored by Shourya Shukla and Christian Couder. He posted 2 final blog posts about it,
+ some [Reflections on Working With the Git Community](https://atharvaraykar.me/gitnotes/final-reflection)
+ and a [Technical Report](https://atharvaraykar.me/gitnotes/final-report).
+
+- ZheNing Hu worked on the
+[Use ref-filter formats in `git cat-file`](https://summerofcode.withgoogle.com/projects/#6499923274498048)
+ project. He was co-mentored by Hariom Verma and Christian Couder and posted
+[a final blog post about it](https://adlternative.github.io/GSOC-Git-Final-Blog/).
 
 <!---
 ### Reviews