diff --git a/README.md b/README.md
index 60bfea4..2626322 100644
--- a/README.md
+++ b/README.md
@@ -27,7 +27,7 @@ Gem:
 
 ## Configuration
 
-Add `factory_bot_rails` to your Gemfile:
+Add `factory_bot_rails` to your Gemfile in both the test and development groups:
 
 ```ruby
 group :development, :test do