message: Update README.md with new build instructions
diff: @@ -77,21 +77,41 @@ devtools::install_github("tensorflow/io", subdir = "R-package")
  ### Python
  -The TensorFlow I/O package (`tensorflow-io`) could be built from source:
  +For Python development, a reference Dockerfile [here](dev/Dockerfile) can be
  +used to build the TensorFlow I/O package (`tensorflow-io`) from source:
  ```sh
  -$ docker run -it -v ${PWD}:/working_dir -w /working_dir tensorflow/tensorflow:custom-op
  -$ # In docker
  -$ curl -OL https://github.com/bazelbuild/bazel/releases/download/0.20.0/bazel-0.20.0-installer-linux-x86_64.sh
  -$ chmod +x bazel-0.20.0-installer-linux-x86_64.sh
  -$ ./bazel-0.20.0-installer-linux-x86_64.sh
  -
  +$ # Build and run the Docker image
  +$ docker build -f dev/Dockerfile -t tfio-dev .
  +$ docker run -it -rm --net=host -v ${PWD}:/v -w /v tfio-dev
  +$ # In Docker, configure will install TensorFlow or use existing install
  $ ./configure.sh
  -$ bazel build //tensorflow_io/...
  -$ python setup.py --data bazel-bin -q bdist_wheel
  +$ # Build TensorFlow I/O C++
  +$ bazel build -s --verbose_failures //tensorflow_io/...
  +$ # Run tests with PyTest, note: some tests require launching additional containers to run (see below)
  +$ pytest tests/
  +$ # Build the TensorFlow I/O package
  +$ python setup.py bdist_wheel
  ```
  A package file `dist/tensorflow_io-*.whl` will be generated after a build is successful.
  +NOTE: When working in the Python development container, an environment variable
  +`TFIO_DATAPATH` is automatically set to point tensorflow-io to the shared C++
  +libraries built by Bazel to run `pytest` and build the `bdist_wheel`. Python
  +`setup.py` can also accept `--data [path]` as an argument, for example
  +`python setup.py --data bazel-bin bdist_wheel`.
  +
  +#### Starting Test Containers
  +
  +Some tests require launching a test container before running. In order
  +to run all tests, execute the following commands:
  +
  +```
  +$ bash -x -e tests/test_ignite/start_ignite.sh
  +$ bash -x -e tests/test_kafka/kafka_test.sh start kafka
  +$ bash -x -e tests/test_kinesis/kinesis_test.sh start kinesis
  +```
  +
  ### R
  We provide a reference Dockerfile [here](R-package/scripts/Dockerfile) for you
  