README.md in secret_env-0.6.1 vs README.md in secret_env-0.7.0

@@ -67,9 +67,14 @@
 
 ## CLI
 
     $ secret_env config/secret_env.yml production your_command --option
 
+or
+
+    $ export SECRET_ENV=production
+    $ secret_env config/secret_env.yml your_command --option
+
 ## Contributing
 
 Bug reports and pull requests are welcome on GitHub at https://github.com/adorechic/secret_env.