Remove obsolete appengine and builder directories

README.md

@@ -6,12 +6,32 @@ This repository contains the source for the Ruby runtime for
 [Google App Engine Flexible](https://cloud.google.com/appengine/docs/flexible/).
 It comprises:
 
-* The base image in the `appengine` directory.
-* The Ruby runtime build pipeline in the `builder` directory.
+* The base image in the `ruby-base` directory.
+* A raw image that contains installations of some common build tools and
+  scripts, including NodeJS, Yarn, and the Google CloudSQL Proxy, in the
+  `ruby-build-tools` directory.
+* An image that analyzes a Ruby application and generates an appropriate
+  Dockerfile, in the `ruby-generate-dockerfile` directory.
+* Templates for the Ruby runtime build pipeline definition in the
+  `ruby-pipeline` directory.
 
 For more information on using the Ruby runtime, see
 https://cloud.google.com/ruby
 
+## Building and testing
+
+The provided Rakefile builds the three images locally and runs the unit tests
+in the test directory. It requires Ruby 2.3 and Docker 17.06 or later.
+
+Actual builds can be done using the build scripts in this directory. The
+`build-ruby-runtime-images.sh` script uses Google Cloud Container Builder to
+build the images and upload them to Google Container Registry. The
+`build-ruby-runtime-pipeline.sh` script creates a Ruby runtime builder
+configuration and uploads it to Google Cloud Storage where it can be used.
+
+The `integration_test` directory contains a sample application that is used
+by the Google Ruby team for internal integration tests.
+
 ## Contributing changes
 
 * See [CONTRIB.md](CONTRIB.md)