README.md in haskell-1.0.0 vs README.md in haskell-1.0.1

@@ -1,17 +1,24 @@
 # Haskell On Ruby
 
 ```rb
 require 'haskell'
+
+# Invoke sandbox for executing ghc
+Haskell.invoke_sandbox!(File.expand_path('../', __FILE__))
+
 Haskell.compile %{
   add :: Integer -> Integer -> Integer
   add x y = x + y
   result = add 1 2
 }
 
 while Haskell.compiling?
-...
+  # wait for....
 end
 
 p Haskell.execute
 #=> 3
+
+# Don't forget to revoke sandbox
+Haskell.revoke_sandbox!
 ```