Certified recruiter flag

[jace]

Companies like HackerEarth regularly list on Hasjob for their clients. They are in our approved list of recruiters who pay for every listing.

We've should make this a flag that shows on the listing. I propose:

1. Recruiter table which lists all the domains used by certified recruiters (should it also include specific email addresses for gmail users?)
2. A certified flag on the listing that is automatically set if the recruiter is found in the recruiter table. This can be manually unset for cases where the recruiter is hiring for themselves.
3. A monthly report that looks for recruiter listings and helps prepare an invoice (manually processed).