Samba NAS with no authentication on RPi

Hi, I'm in the midst of setting up my raspberry pi as a NAS device and have run into a problem, I want this to just be a local drop box style drive for anyone in the house to access, so i do not want any authentication on the drive (otherwise the whole thing would work perfectly with usernames and passwords). I have it pretty much set up apart from this problem, it prompts for a username and password even though there has been no users created on the device, I basically want all guests to be able to read and write. 

I have looked about on other forums but cannot find what they suggest to do, I have accessed the smb.conf and changed "security = user" to "security = share" the next stage is to go a little further down the config and find and set guest account = nobody, I cannot find this option which I assume will make it accessible.

I am accessing the smb.conf via the nano text editor using putty ssh from my main PC and have browsed through all pages to find this config, but with no joy, I thought it may have been the case that I could just add the text into the config, but that didn't work either. 

Any help or advice would be greatly appreciated.

EDIT: I managed to get it working, found a fix on the ubuntu forums which i could apply to raspbian which was actually a code that wasn't working for the user that posted it, but it worked for me, for anyone wanting to know what i used its here:

security = share 
map to guest = bad user

path = /home/shares
available = yes
read only = no
browsable = yes
public = yes
writable = yes
guest ok = yes