Also fixed bug from the sqlite-utils 2.x upgrade caused
by checking db[table].exists instead of db[table].exists()

Closes #38

Refs #35, refs #8. Still needs documentation.

By bumping sqlite-utils dependency to get this fix:
https://github.com/simonw/sqlite-utils/issues/52

Thanks to Jacob Kaplan-Moss: https://twitter.com/jacobian/status/1192510111719313408

Closes #12 and #23

This ensures we don't accidentally fail to create a user record
for the currently authenticated user.

If tables were missing, script would throw an error.

Refs #20

Also added some initial rate limit error handling code.

I moved this test into test_import.py in the previous commit.

Tables with hyphens in the name are harder to query
because you have to remember to [escape-them].