add dockerfile for britpol

[Sparrow0hawk]

Big fan of this package for some personal projects although found some trickiness when installing it on my M1 mac. Therefore I had a go at writing a Dockerfile to containerise the package to enable me to use it from within a container.

Requirements

Need Docker installed on your machine.

Usage

This is a simple Dockerfile that builds a container using the r-base image, installing some library dependencies before installing devtools and using devtools to install britpol form GitHub. On using docker run the container returns an R console from within the container from which you can use the britpol package.

Building

You can build this locally with docker commands:

$ cd britpol/

$ docker build . -t britpol-docker:latest

Running

After docker builds the image you can run it with the following commands:

$ docker run -it britpol-docker:latest

To mount your current directory on your host machine (to egress data):

$ docker run -it -v $PWD:/home/docker britpol-docker:latest

Let us know if you'd be interested in this PR at all and no worries if not.