### What problem does this PR solve?
Not sure why MySQL is inserting empty string in this case, but when I
use postgres I got `null value in column "invited_by" of relation
"user_tenant" violates not-null constraint`
### Type of change
- [X] Bug Fix (non-breaking change which fixes an issue)
### What problem does this PR solve?
_Briefly describe what this PR aims to solve. Include background context
that will help reviewers understand the purpose of the PR._
### Type of change
- [x] New Feature (non-breaking change which adds functionality)