Updated tutorial link to using-herbie

Author: HazardousPeach

README.md

@@ -51,7 +51,7 @@ Running Herbie
 --------------
 
 For details on how to run Herbie, please see the
-[tutorial](http://herbie.uwplse.org/doc/tutorial.html).
+[tutorial](http://herbie.uwplse.org/doc/latest/using-herbie.html).
 
 The format of input files is a Scheme-based language;
 you can find several examples in `bench/`.