Add send_mail job
Send mails as background jobs
Add tests for access privileges to rq-dashboard
Add rq-dashboard dependency
Add RQ-dashboard blueprint to app
Add another job to scheduled tasks
Temporary fix to create the list of queues in Redis
Revert: remove warm_cache from jobs for now as it times out
Lambdas don't get on well with workers
Use forked rq-scheduler repository in PyBossa
remove code fixed by new rq-scheduler version used
Migration to add updated and completed columns.

This migration adds two columns: updated and completed.

Updated is used to keep track about when the project was updated (task,
task_runs, etc.).

Completed is used to know when all the tasks have been marked as completed.
Add two columns: updated, completed.
Update timestamp onupdate event.
Add new update_timestamp method.
Update project.updated timestamp when inserted or updated blog post.
Refactor.
Update project.updated timestamp when new task or updated one.
Update app.updated column when taskrun inserted or updated.
Merge branch 'master' into issue-927-clean-old-projects