message: update README to use postgres info
diff: ## Installing
  -Sign up for the [UPS Developer Kit](https://www.ups.com/upsdeveloperkit?loc=en_US) to get the access key.
  +Following the steps from [data/postgres](../data/postgres/README.md) to install the emissions factors database.
  -Copy `.env.SAMPLE` to `.env` and fill in your UPS username and password and access key in `.env`.
  -You will need a local replicated Orbit DB which you can get with the [Replicate DB script](../orbitdb/README.md) and then fill out the Orbit DB directory (should be `../orbitdb/orbitdb`) and the Orbit DB Address.
  -
  -Sign up for the [Google DistanceMatrix API](https://developers.google.com/maps/documentation/distance-matrix/overview) and [Google Geocode API](https://developers.google.com/maps/documentation/geocoding/overview) and get an access key for both API's.
  -
  -Fill in the Google API key in `.env`.
  +Copy `.env.SAMPLE` to `.env`. You will need to fill in:
  +- Your PostgreSQL username and password.
  +- The Google API key for the [Google DistanceMatrix API](https://developers.google.com/maps/documentation/distance-matrix/overview) and [Google Geocode API](https://developers.google.com/maps/documentation/geocoding/overview).
  +- If you have access to the [UPS Developer Kit](https://www.ups.com/upsdeveloperkit?loc=en_US), your UPS username, password, and access key.
  Make sure you are using node version 16.
  