User:Adamw/old/RFC - Campaigns entities

These improvements to Extension:Campaigns will persist information about campaigns, and provide an API.

Considerations

Not sure if we want to have campaign "owners".
How to deal with fuzz spam?
Do we want any kind of namespacing done on campaigns? Seems wise. This could be done in a semi-transparent way by forming a campaign name like "<group-identifier>/<campaign title>" during campaign creation.

Column	Type	Description
id	unsigned int not null, primary key	Autoincrement id
name	varchar(255) not null, unique key	Campaign name. Cannot be updated.
welcome_title	varchar(255) default null	Page to show during new account creation.
created_time	timestamp not null, key	Campaign creation time
is_private	tinyint not null default 1	True if campaign membership should be hidden from public view

Column	Type	Description
id	unsigned int not null	Autoincremented link table row id
campaign_id	unsigned int not null	FK to campaign.id
user_id	unsigned int not null	FK to user.user_id

This table should be designed more carefully so we are future-compatible with obvious, new Campaigns use cases.

Column	Type	Description
id	unsigned int not null	Autoincremented link table row id
campaign_id	unsigned int not null	FK to campaign.id
user_id	unsigned int not null	FK to user.user_id

There is currently only one class of campaign owner, and these users are allowed to view all information and make any changes to a campaign.

Wikimetrics will pull cohorts via an API that we'll create, to let users access them from Wikimetrics.

Wikimetrics will need to be extended to support this new usage.

Things which need to happen, but are not covered by this RFC:

Admin UI: create campaigns, edit properties, assign owners. Allow the community to create social campaigns.
Campaign link generation
Campaigns for things other than new account creation (e.g. fundraising, editathons)