document new flag

Author: matthewfranglen

README.md

@@ -134,6 +134,10 @@ Optional flags:
 - `-o` to override existing variables.
 - `-v` for increased verbosity.
 
+### Disable load_dotenv
+
+You can disable automatic loading of dotenv values by setting the `DOTENV_AUTOLOAD_DISABLED` environmental variable to `true`. This can be useful if you are using a library that uses `load_dotenv` and you want to manage the environment in a different way.
+
 ## Command-line Interface
 
 A CLI interface `dotenv` is also included, which helps you manipulate the `.env` file