docs: Add note on using credHelpers for multi-registry authentication

Signed-off-by: Arjun Raja Yogidas <[email protected]>

README.md

@@ -220,22 +220,6 @@ contents of your `~/.docker/config.json` file to be:
 This configures the Docker daemon to use the credential helper for all Amazon
 ECR registries.
 
-The Amazon ECR Docker Credential Helper can be used alongside your existing docker login authentication tokens: 
-
-```json
-{
-	"credsStore": "ecr-login",
-	"auths": {
-		"https://index.docker.io/v1/": {
-			"auth": [docker.io-auth-token]
-		},
-		"registry.gitlab.com": {
-			"auth": [gitlab-auth-token]
-		},
-	}
-}
-```
-
 With Docker 1.13.0 or greater, you can configure Docker to use different
 credential helpers for different ECR registries. To use this credential helper for
 a specific ECR registry, create a `credHelpers` section with the URI of your
@@ -253,6 +237,26 @@ ECR registry:
 This is useful if you use `docker` to operate on registries that use different
 authentication credentials.
 
+If you need to authenticate with multiple registries, including non-ECR registries, you can combine credHelpers with auths. For example:
+```json
+{
+  "credHelpers": {
+    "<aws_account_id>.dkr.ecr.<region>.amazonaws.com": "ecr-login"
+  },
+  "auths": {
+      "ghcr.io": {
+        "auth": [GITHUB_PERSONAL_ACCESS_TOKEN]
+      },
+      "https://index.docker.io/v1/": {
+        "auth": [docker.io-auth-token]
+      },
+      "registry.gitlab.com": {
+        "auth": [gitlab-auth-token]
+      }
+	}
+}
+```
+
 ### AWS credentials
 
 The Amazon ECR Docker Credential Helper allows you to use AWS credentials stored in different locations.  Standard ones