The intention is simple: just let me in without asking for password again and again!
Follow the steps to achieve this:
1. Generate RSA key from host machine (skip this if you have already got one)
ssh-keygen -t rsa -C <firstname.lastname@example.org>
Accept the default location and DO NOT give a password to it.
2. Copy the RSA key generated to your remote machine
cat ~/.ssh/id_rsa.pub | ssh root@<remotemachineipaddress> 'cat >> ~/.ssh/authorized_keys'
So far, it is all done.
3. A step further
It would be great if can we save the time on typing the hideous 'SSH' and 'email@example.com' as well, wouldn't it? Set up an alias for it from your host machine then.
alias apple='ssh root@<remotemachineipaddress>'
Put the line into '~/.bashrc' so that it would persist.
And there we go, apple is your new login!