It's 'tweak', not 'modify' now
Merge a forgotten commit from before move:

 Improve the web server Dockerfile:

- create developer user
- make developer user own the source code
- install sudo and make developer a passwordless sudoer
- split long commands with "&&" to multiple lines, but invoke them
  with single RUN to not get too many intermediate images
Another forgotten commit from before move: Fix django 1.7 settings template
Merge last forgotten commit -  Add an info on how to interrupt the assistant