Support "break-out" retros

[davidje13]

For large teams, it can be useful to divide the team into smaller groups for retro facilitation, but it is still useful to store all items and actions in a combined form.

This could be achieved by adding a category to items, and providing filters in the UI. The current /retros/<id> path would continue to show all items, with new /retros/<id>/sub/<category> path which applies the filtering. It may be useful for the main retro to display an indicator (such as a coloured dot) for which sub-retro an item came from (particularly useful when viewing archives).

Behind-the-scenes, the full retro state will continue to be shared to all participants, making this a display-level filter. The retro will continue to have a single password which works for the main retro and all sub-retros.

Retro state will also need to be per-category (current data structure location could continue to be used for whole retro, with a dictionary in a new location for sub-retros). Retro settings (e.g. theme) will apply to all sub-retros and does not need any change.

Handling of uncategorised items is to be decided; they could appear on all sub-retros, or could appear only in the main retro. For action items, it seems useful to display all past items in all sub-retros, but perhaps filter new items.

It may be desirable to offer functionality for dividing participants into sub-retros randomly, but this would presumably need some integration with video conferencing break-out rooms. Pulling all sub-retros back to the main retro may also be desirable (i.e. pushing a redirect to all participants). Both of these features should be split out as separate work.

Archiving will continue to apply to the whole retro.

[davidje13]

The basics for this are now supported, but there is no UI to discover it (accessible by accessing /groups/<id> at the end of the retro URL)

Remaining work:

• add UI for reaching groups
• add UI for showing group-filtered archives (functional URLs already exist)
• show indicator for which group an item came from in main retro and main retro archive
• testing is insufficient, especially for such a complex feature

The code for managing multiple states has become quite messy (several actions have to be aware of which state they are using). It would be nice to tidy that up, but I don't know how while maintaining an atomic dispatcher (being able to modify items and state simultaneously).

[davidje13]

when groups are "active", the main retro screen should block the ability to add new items (and possibly hide the retro entirely), instead showing links to the current sub-retros (and an option to create a new one). This should aid discoverability for new people joining an existing retro (and will avoid them adding items to the main retro, where behaviour is uncertain)

An option could be added to the menu to "activate" sub-retros, then within a sub-retro, an option can be added to return to the main retro (where it is possible to "deactivate" the sub-retros, bringing everybody back to the main retro automatically and returning it to normal functionality)