You need to have your SSH key added to the remote server.
Configure an alias and enable SSH Agent forwarding in ~/.ssh/config
Host nuitdebout.fr
Hostname XXX.XX.XX.XX
User root
ForwardAgent yes
Check if ssh-agent
is running
ssh-add -L
If not, add your key to ssh-agent
ssh-add ~/.ssh/id_rsa.pub
Install capistrano-symfony
Gem
gem capistrano-symfony
Deploy on production
cap production deploy