To install and manage multiple Postgres versions on mac using brew, you can top tinto this repo: https://github.com/petere/homebrew-postgresql
brew tap petere/postgresql
Then, you can
brew install <formula> as needed.
The formulae installed are "keg-only", meaning that they are not linked to /user/bin, thus not getting a
postgresql command in your terminal. You have to access it with a full path to the keg,
You can use the
postgresql-common to manage multiple versions.
If you get an error saying that postgres role does not exist:
** (Mix) The database for HelloPhoenix.Repo couldn't be created, reason given: psql: FATAL: role "postgres" does not exist
/Applications/Postgres.app/Contents/MacOS/bin/createuser -s postgres