We fetch the users from Phabricator based on their Phabricator ID. If
a user with the same username exists and is a member of the project,
we set them as assignee or author.
When a user is applicable, we also cache it in Redis so we don't have
to perform the request again for the same phid.
This sets up all the basics for importing Phabricator tasks into
GitLab issues.
To import all tasks from a Phabricator instance into GitLab, we'll
import all of them into a new project that will have its repository
disabled.
The import is hooked into a regular ProjectImport setup, but similar
to the GitHub parallel importer takes care of all the imports itself.
In this iteration, we're importing each page of tasks in a separate
sidekiq job.
The first thing we do when requesting a new page of tasks is schedule
the next page to be imported. But to avoid deadlocks, we only allow a
single job per worker type to run at the same time.
For now we're only importing basic Issue information, this should be
extended to richer information.
