message: add installation from github source.
diff: @@ -43,8 +43,18 @@ For more details, see the
  ## Installation
  -Install a prebuilt pip package.
  +There are two ways to install Model Maker.
  +
  +* Install a prebuilt pip package.
  ```shell
  pip install tflite-model-maker
  ```
  +
  +* Clone the source code from GitHub and install.
  +
  +```shell
  +git clone https://github.com/tensorflow/examples
  +cd examples/tensorflow_examples/lite/model_maker/pip_package
  +pip install -e .
  +```
  