Update README and remove unused assembler script

tensorflow_runtime_dockerfiles/README.md

 # TensorFlow Runtime Dockerfiles
 
-Simple Dockerfiles for running TensorFlow, with Jupyter variants.
+Simple Dockerfiles for running TensorFlow, with Jupyter and GPU variants.
 
 Maintainer: @angerson (TensorFlow, SIG Build)
+
+* * *
+
+These containers are built by an internal job at Google and published to
+[tensorflow/tensorflow](https://hub.docker.com/r/tensorflow/tensorflow) on
+Docker Hub. Here's a quick way to try out TensorFlow with GPU support and Jupyter:
+
+```bash
+docker run --gpus=all -it --rm -v $(realpath ~/notebooks):/tf/notebooks -p 8888:8888 tensorflow/tensorflow:nightly-gpu-jupyter
+```
+
+Refer to [the tensorflow.org Docker installation
+instructions](https://www.tensorflow.org/install/docker) for more details.
+
+# Building Containers
+
+Builds are straightforward. Here's a sample:
+
+```bash
+docker build --target=base --build-arg TENSORFLOW_PACKAGE=tf-nightly-cpu -t tensorflow-nightly -f cpu.Dockerfile .
+```
+
+Look at the Dockerfiles for full details.
+
+The builds include very simple import tests to verify that the packages work.
+You can run the tests like so:
+
+```bash
+docker build --target=test --build-arg TENSORFLOW_PACKAGE=tf-nightly-cpu -f cpu.Dockerfile .
+docker build --target=base --build-arg TENSORFLOW_PACKAGE=tf-nightly-cpu -t tensorflow-nightly -f cpu.Dockerfile .
+```
+
+The test layer starts from the base layer, so the second command will complete instantly.
+
+# Contributions
+
+If you would like to contribute a small change, please make a pull request. For
+large changes such as support for additional platforms, please clone this
+directory into a new directory and update the README to indicate that you are
+the new maintainer.

tensorflow_runtime_dockerfiles/assembler.sh

-#!/bin/bash
-
-function try() {
-  "$@" || echo "failed: $@" >> log.txt
-}
-
-try docker build --target=jupyter --build-arg TENSORFLOW_PACKAGE=tensorflow-cpu -t tensorflow/tensorflow:latest-jupyter -f cpu.Dockerfile .
-try docker build --target=jupyter --build-arg TENSORFLOW_PACKAGE=tensorflow -t tensorflow/tensorflow:latest-gpu-jupyter -f gpu.Dockerfile .
-try docker build --target=base --build-arg TENSORFLOW_PACKAGE=tensorflow-cpu -t tensorflow/tensorflow:latest -f cpu.Dockerfile .
-try docker build --target=base --build-arg TENSORFLOW_PACKAGE=tensorflow -t tensorflow/tensorflow:latest-gpu -f gpu.Dockerfile .
-
-try docker build --target=jupyter --build-arg TENSORFLOW_PACKAGE=tensorflow-cpu -t tensorflow/tensorflow:latest-jupyter -f cpu.Dockerfile .
-try docker build --target=jupyter --build-arg TENSORFLOW_PACKAGE=tf-nightly-cpu -t tensorflow/tensorflow:nightly-jupyter -f cpu.Dockerfile .
-try docker build --target=jupyter --build-arg TENSORFLOW_PACKAGE=tensorflow -t tensorflow/tensorflow:latest-gpu-jupyter -f gpu.Dockerfile .
-try docker build --target=jupyter --build-arg TENSORFLOW_PACKAGE=tf-nightly -t tensorflow/tensorflow:nightly-gpu-jupyter -f gpu.Dockerfile .
-
-try docker build --target=base --build-arg TENSORFLOW_PACKAGE=tensorflow-cpu -t tensorflow/tensorflow:latest -f cpu.Dockerfile .
-try docker build --target=base --build-arg TENSORFLOW_PACKAGE=tf-nightly-cpu -t tensorflow/tensorflow:nightly -f cpu.Dockerfile .
-try docker build --target=base --build-arg TENSORFLOW_PACKAGE=tensorflow -t tensorflow/tensorflow:latest-gpu -f gpu.Dockerfile .
-try docker build --target=base --build-arg TENSORFLOW_PACKAGE=tf-nightly -t tensorflow/tensorflow:nightly-gpu -f gpu.Dockerfile .
-
-if [[ -s log.txt ]]; then
-  echo "all these failed:"
-  cat log.txt
-  exit 1
-fi