To install redmine, use

sudo apt-get install redmine

1. In the redmine folder /usr/share/redmine/config, copy configuration.yml.example to configuration.yml
2. Edit the configuration.yml file to add the end of the file (Note the indentations, spaces before each line, do matter)

   production:
      email_delivery:
        delivery_method: :smtp
        smtp_settings:
          enable_starttls_auto: true
          address: "smtp.gmail.com"
          port: 587
          domain: "smtp.gmail.com" # 'your.domain.com' for GoogleApps
          authentication: :plain
          user_name: "redmine@psychstat.org"
          password: "xxxxxxxxx"

To automatically fetch emails every 5 minutes, use a cron job. Note to create redmineread and redineerror label in gmail first. If your password is complex enough, remember to quote them.

*/5 * * * * /usr/local/bin/ruby /usr/local/bin/rake -f /usr/share/redmine/Rakefile redmine:email:receive_imap RAILS_ENV="production" host=imap.gmail.com ssl=SSL port=993 move_on_success=redmineread move_on_failure=redmineerror username=redmine@psychstat.org password='xxxxxx' unknown_user=accept no_permission_check=1 project=test allow_override=project,tracker