Implement Collaboration

[michael]

One of the most crucial features that is still missing is collaboration. It should be rather easy to add real collaboration to our current stack, so people can invite other to work on their document.

On the Hub:

• Create table collaborators which is just a mapping user to document
• Adapt API (/users/michael/documents) so users see their own documents plus those docs where they collaborate.

On the Composer:

• Autosync (we should sync automatically so it's less likely to run into conflicts when multiple users are editing the same document)
• Collaborators panel (so you can easily invite new people)
• Optimize dashboard (we need to visually separate your own docs from docs where you're a collaborator)

General thoughts:

• Old Substance supported invitation by email (using a temporary TAN code that needs to be confirmed by the invited user, which may not yet have a substance account), it was fairly complex to implment, so maybe we wanna start by inviting existing substance users.
• Notification system: We sort of need a notification system in the long run. There could be a message reading for instance: "Michael invited you to collaborate on his document 'Substance'".

I guess it's rather cheap so maybe this should be part of the 0.2.0 release. What do you think?

[michael]

Add on thought:

• Anyone should be able to open any Substance document and add annotations (idea, question, error) and comments. Only "collaborators" are

Maybe we should display the active discussion on the hub (published publication) as well.

[obuchtala]

I suppose, this is done.