Add note about not requiring a profile if creds are in the environment

@@ -40,6 +40,9 @@ Where ``command`` is one of:
 The ``config file`` is a YAML format file containing all of the information
 about your Lambda function.
 
+If you use environment variables for your AWS credentials (as normally supported by boto),
+simply exclude the ``profile`` element from the YAML file.
+
 An example project based on a Kinesis stream can be found in
 [samples/kinesis](https://github.com/garnaat/kappa/tree/develop/samples/kinesis).
 
@@ -56,4 +59,4 @@ The basic workflow is:
 * Run ``kappa --config <path-to-config> tail`` to see more output
 
 If you have to make changes in your function or in your IAM roles, simply run
-``kappa deploy`` again and the changes will be uploaded as necessary.
\ No newline at end of file
+``kappa deploy`` again and the changes will be uploaded as necessary.