This commit improves the Gitpod setup. It now allows you to benefit from prebuilds.
Also, Gitpod now waits until the server is ready before opening a preview window.
* Unset DATABASE_URL in .gitpod.yml
* Only run bin/setup once
* Try alternative approach for unsetting DATABASE_URL
* Update bin/setup
* Consistently use db_url
* Fix bug caused by typo (= instead of ==)