Is your feature request related to a problem? Please describe.
Our data sources have paths longer than 50 characters. This seems like an unnecessarily short limit for this field.

Describe the solution you'd like
A string limit of 255 characters feels more appropriate for a URI.

Describe alternatives you've considered
I considered requesting sqlalchemy.types.Text as the type instead, an unlimited string field.

Additional context
Add any other context or screenshots about the feature request here.