Update postgres schema and wipe the accrued migrations

[steve-fischer-200]

It will make it easier for developers to understand the schema if it is kept up-to-date, rather than having to review all the migrations.

[Foxcapades]

init.sql is/was intended to always stay up to date with the most recent definition of what the database should be. The migrations are just there as an extra (unneeded?) robustness feature that allow old databases to be pulled up to date without being nuked.

This task is basically just manually applying migrations 1.3.0 and 1.3.6 to the init.sql file.