From 2.6.x to 2.7.0

1. Stop server & resque

2. Update code & db

# You may want to add 
# sudo -H -u gitlab 
# before each script

# Get latest code
git pull origin stable

# !!! Config should be replaced with a new one. Check it after replace
cp config/gitlab.yml.example config/gitlab.yml

# Install libs
bundle install --without development test

# update db
bundle exec rake db:migrate RAILS_ENV=production

3. Start web server & Resque