doc(README.md): use the correct lookup order for S3 env vars

Author: Aaron Schlesinger

README.md

@@ -17,8 +17,8 @@ The builder is primarily a git server that responds to `git push`es from clients
 1. Executes the `git-receive-pack` or `git-upload-pack` hooks (as appropriate)
 2. Calls `git archive` to produce a tarball (i.e. a `.tar.gz` file) on the local file system
 3. Saves the tarball to centralized object storage according to the following rules:
-  - If the `DEIS_MINIO_SERVICE_HOST` and `DEIS_MINIO_SERVICE_PORT` environment variables exist, saves to the [S3 API](http://docs.aws.amazon.com/AmazonS3/latest/API/APIRest.html) compatible server at `http://$DEIS_MINIO_SERVICE_HOST:$DEIS_MINIO_SERVICE_HOST`
-  - Otherwise, if the `DEIS_OUTSIDE_STORAGE` environment variable exists, saves to `https://$DEIS_OUTSIDE_STORAGE`.
+	- If the `DEIS_OUTSIDE_STORAGE` environment variable exists, saves to the [S3 API](http://docs.aws.amazon.com/AmazonS3/latest/API/APIRest.html) compatible server at `https://$DEIS_OUTSIDE_STORAGE`
+  - Otherwise, if the `DEIS_MINIO_SERVICE_HOST` and `DEIS_MINIO_SERVICE_PORT` environment variables exist (these are standard [Kubernetes service discovery environment variables](http://kubernetes.io/docs/user-guide/services/#environment-variables)), saves to the [S3 API](http://docs.aws.amazon.com/AmazonS3/latest/API/APIRest.html) compatible server at `http://$DEIS_MINIO_SERVICE_HOST:$DEIS_MINIO_SERVICE_HOST`
 4. Starts a new [Kubernetes Pod](http://kubernetes.io/docs/user-guide/pods/) to build the code, according to the following rules:
   - If a `Dockerfile` is present in the codebase, starts a [`dockerbuilder`](https://github.com/deis/dockerbuilder) pod, configured to download the code to build from the URL computed in the previous step.
   - Otherwise, starts a [`slugbuilder`](https://github.com/deis/slugbuilder) pod, configured to download the code to build from the URL computed in the previous step.