Merge pull request #570 from rust-lang/docs-document-releases-distrib…

…ution-lambdas

docs: document releases-distribution lambdas

terragrunt/modules/release-distribution/README.md

@@ -11,3 +11,14 @@ distribution of traffic between CloudFront and Fastly.
 If you want to use a specific CDN, use `fastly-static.rust-lang.org` or `cloudfront-static.rust-lang.org`.
 
 The Fastly CDN is configured via the VCL language, while the CloudFront CDN is configured via Javascript AWS lambda functions.
+
+## Lambdas
+
+The following lambdas manage requests starting with the following URLs:
+
+- [doc-router](./lambdas/doc-router/index.js):
+  - dev: dev-doc.rust-lang.org
+  - prod: doc.rust-lang.org
+- [static-router](./lambdas/static-router/index.js):
+  - dev: dev-static.rust-lang.org
+  - prod: static.rust-lang.org