added asciicast brain gcd

Author: Cheshire-12

README.md

@@ -25,4 +25,7 @@
 [![asciicast](https://asciinema.org/a/I7Qv5wFHbpgsqohyveU8xQvWK.svg)](https://asciinema.org/a/I7Qv5wFHbpgsqohyveU8xQvWK)
 
 ### Brain calculator game
-[![asciicast](https://asciinema.org/a/A7NkDB611mGA9oPoh7vu8TRM0.svg)](https://asciinema.org/a/A7NkDB611mGA9oPoh7vu8TRM0)
+[![asciicast](https://asciinema.org/a/A7NkDB611mGA9oPoh7vu8TRM0.svg)](https://asciinema.org/a/A7NkDB611mGA9oPoh7vu8TRM0)
+
+### Brain greatest common divisor game
+[![asciicast](https://asciinema.org/a/ylHyfvqJD3U4Vq9omSqaU1TO8.svg)](https://asciinema.org/a/ylHyfvqJD3U4Vq9omSqaU1TO8)