Update README.md

Author: oubiwann

README.md

@@ -7,7 +7,7 @@ resources
 
 * 1991 - 1993: An [early Haskell](http://www.cs.cmu.edu/afs/cs/project/ai-repository/ai/lang/lisp/code/syntax/haskell/0.html) written in Lisp (source code: [github import](https://github.com/haskell-lisp/yale-haskell))
 * 2006: [Writing A Lisp Interpreter In Haskell](http://www.defmacro.org/ramblings/lisp-in-haskell.html)
-* 2006: present - [Write Yourself a Scheme in 48 Hours](http://en.wikibooks.org/wiki/Write_Yourself_a_Scheme_in_48_Hours)
+* 2006 - present: [Write Yourself a Scheme in 48 Hours](http://en.wikibooks.org/wiki/Write_Yourself_a_Scheme_in_48_Hours)
 * 2007: [Liskell - Haskell Semantics with Lisp Syntax](http://clemens.endorphin.org/ILC07-Liskell-draft.pdf)
 * 2010: (Historic) [Lisk](http://chrisdone.com/posts/lisk-lisp-haskell) ([preserved code](https://github.com/haskell-lisp/historic-lisk))
 * 2010 - present: [Husk Scheme](http://justinethier.github.io/husk-scheme/)