docs: update the readme docker [skip ci]

Author: aminya

README.md

@@ -179,7 +179,8 @@ jobs:
 Here is an example for using setup_cpp to make a builder image that has the Cpp tools you need.
 
 ```dockerfile
-FROM ubuntu:devel
+#### Base Image
+FROM ubuntu:devel AS base
 
 # add setup_cpp
 WORKDIR "/"
@@ -189,12 +190,25 @@ RUN wget --no-verbose "https://github.com/aminya/setup-cpp/releases/download/v0.
 RUN chmod +x ./setup_cpp_linux
 
 # install llvm, cmake, ninja, and ccache
-RUN ./setup_cpp_linux --compiler llvm --cmake true --ninja true --ccache true
-
-# activate cpp environment variables
-RUN source ~/.cpprc
+RUN ./setup_cpp_linux --compiler llvm --cmake true --ninja true --ccache true --vcpkg true --make true
 
+CMD source ~/.cpprc
 ENTRYPOINT [ "/bin/bash" ]
+
+#### Building
+FROM base AS builder
+ADD ./dev/cpp_vcpkg_project /home/app
+WORKDIR /home/app
+RUN bash -c 'source ~/.cpprc \ 
+    && make build'
+
+### Running environment
+# use a distroless image or ubuntu:devel if you wish
+FROM gcr.io/distroless/cc
+# copy the built binaries and their runtime dependencies
+COPY --from=builder /home/app/build/my_exe/Release/ /home/app/
+WORKDIR /home/app/
+ENTRYPOINT ["./my_exe"]
 ```
 
 See [this folder](https://github.com/aminya/setup-cpp/tree/master/dev/docker), for some dockerfile examples.

dev/docker/ubuntu.dockerfile

@@ -22,6 +22,7 @@ RUN bash -c 'source ~/.cpprc \
     && make build'
 
 ### Running environment
+# use a distroless image or ubuntu:devel if you wish
 FROM gcr.io/distroless/cc
 # copy the built binaries and their runtime dependencies
 COPY --from=builder /home/app/build/my_exe/Release/ /home/app/

dev/docker/ubuntu_node.dockerfile

@@ -21,6 +21,7 @@ RUN bash -c 'source ~/.cpprc \
     && make build'
 
 ### Running environment
+# use a distroless image or ubuntu:devel if you wish
 FROM gcr.io/distroless/cc
 # copy the built binaries and their runtime dependencies
 COPY --from=builder /home/app/build/my_exe/Release/ /home/app/

dev/docker/ubuntu_stable_node.dockerfile

@@ -29,6 +29,7 @@ RUN bash -c 'source ~/.cpprc \
     && make build'
 
 ### Running environment
+# use a distroless image or ubuntu:20.04 if you wish
 FROM gcr.io/distroless/cc
 # copy the built binaries and their runtime dependencies
 COPY --from=builder /home/app/build/my_exe/Release/ /home/app/