EPIC: Team Mode

As a member of a **`team`** of people
needing to be more effective at _collaborating_ on a project (_collection of tasks AKA `list` of `items`_)
I want a way of **visualise** what my team-mates are working on, who is assigned to what task and
see when people are "stuck" or "blocked" and help them move forward.

This is a "_Mega_ Epic" there will be _many_ features built in order to achieve our desired result. ⏳
We're starting as simple as possible with just the ability to share a `list` of `items` with one or more people. 👥
If you have read good books or articles on teamwork/collaboration on highly creative work, please share!

# Todo

+ [ ] Allow a `person` to create a `group` that lets them share an `item` with one or more `people` https://github.com/dwyl/auth/issues/220

## How _you_ can help?

Please comment on this issue by sharing any _useful_ features are for improving teamwork/collaboration, visibility, accountability and _collectively_ "level up" by sharing/delegating, commenting on a task/activity.

Start by reviewing the team-sharing goal and the referenced dwyl/auth issue #220, which covers creating a group for sharing an item with people. Done means a person can create a group and share a list of items with one or more people; the broader collaboration features remain unspecified.

Written by the indexing model from the issue text.