Reproup a haskell section in readme

README.md

@@ -2,10 +2,12 @@
 
 Experiment with Haskell language.
 
-## Compile
+## Work with Haskell
+
+### Compile
 
 `ghc mymainfile`
 
-## Interactive
+### Interactive
 
 `ghci mymainfile`