Factor out ensureUser and add Error class in seed_db
Also removed the seed_many stuff, this will be moved to a seperate
url with in a more generic approach.
Patch by: Sverre Rabbelier
Coverage: code coverage testing for Python
Coverage.py is a Python module that measures code coverage during test execution.
It uses the code analysis tools and tracing hooks provided in the Python standard
library to determine which lines are executable, and which have been executed.
For more information, see http://nedbatchelder.com/code/modules/coverage.html