svn update without password

first techi post from me.
I was setting up Cruise control on ubuntu box. cruisecontrol does svn update periodically and it was asking for interactive password for svn update from server. and it was failing. so I needed to set passwordless svn update on our dev m/c. I struggled bit but finally found the solution.
also got fundaes cleared abt how public-key cryptography works? :).

steps to setup,

1) generate private-public key pair on staging (remote server) using cmd
ssh-keygen -t
it will generate 2 keys id_rsa and id_rsa.pub. copy them to .ssh dir.

2) chmod 600 .ssh/rsa_id

3) copy private key from staging to .ssh dir on dev m/c
cd .ssh
scp user@staging:~/.ssh/id_rsa .
chmod 600 rsa_id

4) connect or do svn update from dev m/c to staging without password