Redis buffering and bugfixes

[mokaddem]

Feature and updates

• Addition of a redis buffer between zmq and dispatcher
• Updated readme
• Database organization in doc/DOC.md
• Message passing schema in doc/message_passing.png

  Bugfixes

• Tons of bug fixes due to code migration (moved handle_contribution from zmq_subscriber to contributor_helper)
• Prevent putting none data if coordinates could not be deduced from phone number.

  UI

• Limited display of top contrib. org. to 10 results instead of unlimited
• Resized badges so that the modal fits in the page without scrolling

[adulau]

Looks very good! Just a small thing to improve would be the logging mechanisms (as there are still a lot of print statements) and that we use standard logging library in Python to support file logging, syslog logging or stdout logging with different level.

[mokaddem]

Good point! Will be done for the next PR.

[adulau]

@mokaddem thank you!