README.md in rubocop-springest-0.6.7 vs README.md in rubocop-springest-0.6.8

@@ -14,9 +14,11 @@
 ```
 
 **.rubocop.yml**
 
 ``` yaml
+require: rubocop-performance
+
 inherit_gem:
   rubocop-springest:
     - config/default.yml
     - config/rails.yml
 ```