#4 Duplicate entries seeded

[Nick-StormID]

If the candidate runs npm i more than once, the three test TODOs are duplicated by the seeding step.
To avoid these duplications, and the confusion that can occur when these duplicates appear, I suggest we clear the db prior to seeding.

An implication of this is that any entries added by the candidate through their UI as they develop a solution will be cleared/lost.
For the intended use of this project I see this as a lesser issue than the duplicate entries. Nevertheless, this side effect should be indicted in the README.