Build the image with:

sudo docker build -t bcl/centos7-haskell .

Run the container with:

sudo docker run -it --name=A_UNIQUE_NAME -v $PWD:/working/:Z --env LOCAL_UID=`id -u` bcl/centos7-haskell bash

The /working/ directory inside the container will be mounted to the current
directory and the 'user' user id will match your UID.

Run it with --env LOCAL_USERNAME=root and it will run as root instead.