fixed typo in README.md

fixed typo in README.md "you will want use"

README.md

@@ -116,7 +116,7 @@ can still use `docker-compose` to run supplementary services like MySQL, etc.).
 If not using `docker-compose`, be sure MySQL is installed (`$``brew install mysql`
 if not) and running (`$``mysql.server start` if not).
 
-On OS X, you'll want use `rbenv` (and `ruby-build`) in order to isolate the
+On OS X, you'll want to use `rbenv` (and `ruby-build`) in order to isolate the
 version of Ruby used here (and to prevent it from conflicting with other
 projects). `bundler` is similarly used to localize gem dependencies.