Upgrade Postgres 9.4 to 9.5 (Homebrew)

migrate-postgres-9.4-to-9.5.txt

These instructions are taken from: Keita's Blog - https://kkob.us/2016/01/09/homebrew-and-postgresql-9-5/

1. Turn PostgreSQL off first, just in case:
  $ launchctl unload ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist

2. Update PostgreSQL itself:
  $ brew update && brew upgrade postgresql

3. Make a new, pristine 9.5 database:
  $ initdb /usr/local/var/postgres9.5 -E utf8

4. Migrate the data to the new 9.5 database:
  $ pg_upgrade \
    -d /usr/local/var/postgres \
    -D /usr/local/var/postgres9.5 \
    -b /usr/local/Cellar/postgresql/9.4.5_2/bin/ \
    -B /usr/local/Cellar/postgresql/9.5.0/bin/ \
    -v
    
5. Move 9.5 data directory back to where PostgreSQL expects it to be:
  $ mv /usr/local/var/postgres /usr/local/var/postgres9.4
  $ mv /usr/local/var/postgres9.5 /usr/local/var/postgres

6. Start PostgreSQL back up!
  $ launchctl load ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist

** Note: If you’re using the pg gem for Rails, you should recompile:
  $ gem uninstall pg
  $ gem install pg