README: Adds more "Similar Projects"

Author: hoijui

README.md

@@ -49,11 +49,28 @@ of the [Git source code control system][git].
     alt="Open Source Ecology Germany logo"
     height="128">][OSEG]
 
-## Related
+## Similar Projects
 
+- [GeeksForGeeks - Git Internals](
+  https://www.geeksforgeeks.org/git-internals/);
+  a very short intro to the topic.
+- [A Beginner’s Guide to Git and Git Internals](
+  https://medium.com/geekculture/a-beginners-guide-to-git-and-git-internals-1e7dcd89d65e)
 - [Git Book - Git Internals (chapter 10)](
   https://git-scm.com/book/en/v2/Git-Internals-Plumbing-and-Porcelain);
   the official documentation about Git internals.
+- [A Visual Guide to Git Internals](
+  https://www.freecodecamp.org/news/git-internals-objects-branches-create-repo/)
+- _Git’s database internals_; GitHub's shot at the topic,
+  in parts:
+  1. [packed object store](
+      https://github.blog/open-source/git/gits-database-internals-i-packed-object-store/)
+  2. [commit history queries](
+      https://github.blog/open-source/git/gits-database-internals-ii-commit-history-queries/)
+  3. [file history queries](
+      https://github.blog/open-source/git/gits-database-internals-iii-file-history-queries/)
+  4. [distributed synchronization](
+      https://github.blog/open-source/git/gits-database-internals-iv-distributed-synchronization/)
 
 [CC-BY-SA-3.0]: https://creativecommons.org/licenses/by-sa/3.0/
 [git]: https://git-scm.com/