* show blurb for tag sponsors
* check that sponsorhip is live and account for expiration time
* automatically add expiration date to tags
* update tag offering
* rewrite tag auto expiration
* night mode compatibility for sponsor logos
* fix spec
* update specs
* Small css adjustment
* Add Sponsorship model
* Add Sponsorship to admin
* Add correct relationships between models
* Add temporary script to migrate sponsorship data
* Use constants for enums
* Use Sponsorship model in PartnershipsController
* Use Sponsorship in the views
* Validate sponsorship levels and tag combos
* Replace the rest of the sponsorship code to use Sponsorship
* Transform GET sign in links into POST
* Ignore CVE-2015-9284 for now
* Update app/views/layouts/_signup_modal.html.erb
Co-Authored-By: Mac Siri <krairit.siri@gmail.com>
* Modify sponsorship copy
* Update sponsorship stuff
* Fix spec and add tag sponsorship
