Add “gravatar.com” to /etc/hosts, pointing to a bogus host or localhost, so it doesn't send traffic their way before you have a chance to disable the functionality

echo '127.0.0.1 gravatar.com' >> /etc/hosts

We have to set up smarthosting with SMTP AUTH, so the server can send mail.

touch /etc/postfix/relay_passwd
chmod 600 /etc/postfix/relay_passwd
echo '[smtp.relay.com]:25 username:password' >> /etc/postfix/relay_passwd

Then stick the following in /etc/postfix/main.cf:

relayhost                  = [smtp.relay.com]:25

smtp_use_tls               = yes
smtp_sasl_auth_enable      = yes
smtp_sasl_password_maps    = hash:/etc/postfix/relay_passwd
smtp_sasl_security_options =

/etc/gitlab/gitlab.rb

## Change the external_url to the address your users will type in their browser
external_url 'https://gitlab.daaave.org/'

## Update settings in the actual configuration file (gitlab-ctl reconfigure
## will apply these settings)
## /opt/gitlab/embedded/service/gitlab-rails/config/gitlab.yml

## Disable Gravatar
gitlab_rails['gravatar_enabled']   = 'false'
gitlab_rails['gravatar_plain_url'] = 'http://gitlab.daaave.org/avatar/${email}'
gitlab_rails['gravatar_ssl_url']   = 'https://gitlab.daaave.org/avatar/${email}'

## Allow users to sign themselves up for accounts
gitlab_rails['gitlab_signup_enabled'] = 'true'

## SSL setup
## You also need to make sure external_url is https
nginx['redirect_http_to_https'] = 'true'
nginx['ssl_certificate']        = '/etc/gitlab/ssl/gitlab.crt'
nginx['ssl_certificate_key']    = '/etc/gitlab/ssl/gitlab.key'

## Enable Redmine integration
## Haven't actually tried this yet
#gitlab_rails['issues_tracker_redmine_title']         = 'Redmine'
#gitlab_rails['issues_tracker_redmine_project_url']   = 'http://redmine.domain.com/projects/:issues_tracker_id'
#gitlab_rails['issues_tracker_redmine_issues_url']    = 'http://redmine.domain.com/:project_id/:issues_tracker_id/:id'
#gitlab_rails['issues_tracker_redmine_new_issue_url'] = 'http://redmine.domain.com/projects/:issues_tracker_id/issues/new'

## EOF
########