Fix --aliases in README.

ab · ab · commit 2190be91922d · 2015-11-13T15:08:15.000-08:00
diff --git a/README.md b/README.md
@@ -22,5 +22,5 @@ the output.
 ```
 $ rbenv each bundle install
 $ rbenv each -v rake test
-$ rbenv each --skip-aliases bundle check
+$ rbenv each --aliases bundle check
 ```
