Run 
  docker build -t <IMAGENAME> .
in this directory to mimic what drone-io does.
  <IMAGENAME> abides to the following convention:
     <USERNAME>/<IMAGENAME>:<TAG>
  Typical:
     parsec/drone-io:v1.0

If anything fails and you want to debug, run
  docker images
Your image is one recent with no name (the name is given
only if the build command succeeded). Copy the IMAGE ID, and run
  docker run -t -i <IMAGE ID> /bin/bash
parsec should be cloned, configured, and compiled in /parsec
Everything is done as root (in the virtual image).

Run docker ps -a
to list the containers still running. docker rm <CONTAINER ID> to
remove the stall processes

Run docker images to list images
Run docker rmi <IMAGE ID> to remove stall images

It is necessary to sync by hand the Dockerfile and the drone-io
configuration commands in
  https://drone.io/bitbucket.org/icldistcomp/parsec/admin

The list of compiler packages is just a guess. It is unspecified on
drone.io what packages are installed when declaring a C program.
