TODO
====

* scape strings before executing scripts in order to prevent exploits: django templates automatically scapes things. Most important is to ensuer that all escape ' to &quot
* Optimize SSH: pool, `UseDNS no`
* Don't store passwords and other service parameters that can be changed by the services i.e. mailman, vps etc. Find an execution mechanism that trigger `change_password()`

* abort transaction on orchestration when `state == TIMEOUT` ?
* filter and other user.is_main refactoring 
* use format_html_join for orchestration email alerts

* generic form for change and display passwords and crack change password form
* enforce an emergency email contact and account to contact contacts about problems when mailserver is down

* add `BackendLog` retry action
* move invoice contact to invoices app?
* wrapper around reverse('admin:....') `link()` and `link_factory()`
* PHPbBckendMiixin with get_php_ini
* Apache: `IncludeOptional /etc/apache2/extra-vhos[t]/account-site-custom.con[f]`
* rename account.user to primary_user
* webmail identities and addresses
* cached -> cached_property
* user.roles.mailbox its awful when combined with addresses:
    * address.mailboxes filter by account is crap in admin and api
    * address.mailboxes api needs a mailbox object endpoint (not nested user)
    * Its not intuitive, users expect to create mailboxes, not users!
    * Mailbox is something tangible, not a role!
* System user vs virtual user:
    * system user automatically hast @domain.com address :(

* use Code: https://github.com/django/django/blob/master/django/forms/forms.py#L415 for domain.refresh_serial()
* Permissions .filter_queryset()


* git deploy in addition to FTP?
* env vars instead of multiple settings files: https://devcenter.heroku.com/articles/config-vars ?
* optional chroot shell?

* make sure prefetch_related() is used correctly 
Remember that, as always with QuerySets, any subsequent chained methods which imply a different database query will ignore previously cached results, and retrieve data using a fresh database query. 
* profile select_related vs prefetch_related

* use HTTP OPTIONS instead of configuration endpoint, or rename to settings?