docs: update readme

README.md

@@ -1,8 +1,28 @@
 # fatalspin
 
-A little tool that kills a random process in your unix system.
+A little tool that kills a random process in your unix system, written in C.
 
-It's written in C and has a little easter egg.
+## Why?
+
+I just did it for fun.
+
+Really, no other reason. 
+
+Be bold : build and run it without reading the code using root privileges.
+
+## How to build
+
+```sh
+make
+```
+
+## How to run
+
+```sh
+./fatalspin
+```
+
+Hint : maybe there's a way for you to find which process was killed (without reading the code).
 
 ## License