README.md in naver-searchad-api-0.0.1 vs README.md in naver-searchad-api-0.0.2

@@ -87,10 +87,11 @@
 [Naver Searchad API authorization](http://naver.github.io/searchad-apidoc/#/samples) is used to authorize applications.
 
 ### Authorization using environment variables
 
 The [Naver Searchad API Auth](https://github.com/forward3d/naver-searchad-api/blob/master/lib/naver/searchad/api/auth.rb) also supports authorization via
-environment variables. Simply set the following variables for your application:
+environment variables if you do not want to check in developer credentials
+or private keys. Simply set the following variables for your application:
 
 ```sh
 NAVER_API_KEY="YOUR NAVER DEVELOPER API KEY"
 NAVER_API_SECRET="YOUR NAVER DEVELOPER API SECRET"
 NAVER_API_CLIENT_ID="YOUR NAVER DEVELOPER CLIENT ID"