add head request response. Fix #309
404 now has HEAD response as well
Merge branch 'master' of https://github.com/biocore/american-gut-web into issue-309
proper checks on user email and insertion
add missing underscore
add missing sets to sql
Merge pull request #329 from squirrelo/fix-addAGLogin

fix addAGLogin
proper 404 header
Merge pull request #330 from squirrelo/add-sets-to-sql

Add missing sets to sql
Merge pull request #327 from squirrelo/issue-309

Add head request response. Fix #309