Update README.md

Docker image info added

README.md

@@ -41,6 +41,35 @@ cmake -DBOOST_ROOT="$BOOST_ROOT" -DCMAKE_BUILD_TYPE=Release
 make -j$(nproc)
 
 make install # this can install the executable files under /usr/local
+```
+
+docker build -t peerplays .
+
+## Docker image
+
+```
+# Install docker
+sudo apt install docker.io
+
+
+# Add current user to docker group
+sudo usermod -a -G docker $USER
+# You need to restart your shell session, to apply group membership
+# Type 'groups' to verify that you are a member of a docker group
+
+
+# Build docker image (from the project root, must be a docker group member)
+docker build -t peerplays you.
+
+
+# Start docker image
+docker start peerplays
+
+# Exposed ports
+# # rpc service:
+# EXPOSE 8090
+# # p2p service:
+# EXPOSE 1776
 ```
 
  Rest of the instructions on starting the chain remains same.