Update documentation

Author: namannandan

cpp/README.md

@@ -4,6 +4,24 @@
 * GCC version: gcc-9
 * cmake version: 3.18+
 * Linux
+
+For convenience, a docker container can be used as the development environment to build and install Torchserve CPP
+```
+cd serve/docker
+# For CPU support
+./build_image.sh -bt dev -cpp
+# For GPU support
+./build_image.sh -bt dev -g [-cv cu121|cu118] -cpp
+```
+
+Start the container and optionally bind mount a build directory into the container to persist build artifacts across container runs
+```
+# For CPU support
+docker run [-v /path/to/build/dir:/serve/cpp/_build] -it pytorch/torchserve:cpp-dev-cpu /bin/bash
+# For GPU support
+docker run --gpus all [-v /path/to/build/dir:/serve/cpp/_build] -it pytorch/torchserve:cpp-dev-gpu /bin/bash
+```
+
 ## Installation and Running TorchServe CPP
 This installation instruction assumes that TorchServe is already installed through pip/conda/source. If this is not the case install it after the `Install dependencies` step through your preferred method.
 
@@ -22,7 +40,7 @@ Then build the backend:
 ```
 ## Dev Build
 cd cpp
-./build.sh [-g cu121|cu118]
+./build.sh
 ```
 
 ### Run TorchServe

docker/Dockerfile.cpp

@@ -1,6 +1,6 @@
 # syntax = docker/dockerfile:experimental
 #
-# This file can build images for CPU with CPP backend support.
+# This file can build images for CPU & GPU with CPP backend support.
 #
 # Following comments have been shamelessly copied from https://github.com/pytorch/pytorch/blob/master/Dockerfile
 #