Restructure repo

Switch from puma to unicorn

Cleanup db management

There is an issue with multiple open connections when dropping the db
through the migrations

Update the schema.sql with 007 migration

The schema.sql file was introduced in parallel to the changes in 006
which is why they weren't introduced in the same commit

Fix asset lookup
Merge pull request #57 from codeforamerica/cleanup-structure

Restructure repo