README.md in frontkick-0.4.7 vs README.md in frontkick-0.4.8

@@ -56,12 +56,13 @@
 
 ### Kill Child Option
 
 On receiving INT and TERM signal, kill the kicked child process before exiting
 
-    Frontkick.exec("sleep 100", :kill_child => true)
+    Frontkick.exec(["sleep 100"], :kill_child => true)
 
 NOTE: This uses Kernel.trap inside.
+NOTE: Shoud use `[]` form, otherwirse `sh -c 'sleep 100'` is ran, and frotkick kills sh process, but sleep process remains
 
 ### Hint: Redirect stderr to stdout
 
 Frontkick itself does not aid anything, but you can do as