ui: horizon graphs

[aspiers]

Description

I think horizon graphs will be an ideal technique for clearly visualising comparative trends of meeting frequencies over time. For example, imagine if rather than representing the trends in the prices of various foods over time, the horizon graphs below instead represented the frequencies of meetings of various organizations with a given minister or government office as they vary over time, or the frequencies of meetings of various ministers or government offices with a given organization:

Comments, Questions and Considerations

There are at least two d3 plugins already providing horizon graph generation. The best one seems to be http://kmandov.github.io/d3-horizon-chart/. Check out this cool example!

Acceptance Criteria

This story can be considered done when the following acceptance tests
are satisfied:

Given access to the MUTI frontend

When I click a certain button or link

Then I see many stacked horizon graphs showing the trends of meeting frequencies over time, where each graph would be equivalent to one bubble in the existing bubble chart visualisation.