Add SDL runtime dependency instruction

README.md

@@ -2,6 +2,15 @@
 
 A remake of pong up to 4 players
 
+# Run
+
+You need `SDL1` runtime to run distributable executable.
+
+```sh
+$ sudo apt install libsdl1.2debian
+$ ./pongcircle
+```
+
 # Build
 
 You need `make` and `SDL1` to build this project.