Add users to the demo server

AddUsers

Get email  Id of the new user : [email protected]

If the user has sent thier public key, skip directly to step 2


1) Generate the new keypair in your mac
=======In you mac=====================

ssh-keygen -t rsa -C "youremailaddress"

You would see the following prompts:
Enter file in which to save the key (/Users/vishwas/.ssh/id_rsa): [Type] yourname
Enter passphrase:[Leave this empty, just hit enter]

You would now see two keys:
yourname   [this is the provate key]
yourname.pub [this is the public key]

Now, copy the public key to your clipboard (you can do it on the command line by)

pbcopy < yourname.pub


[You can test it by pasting on sublime text / notepad etc]


2) Append the key in the demo server

login to the demo server:

ssh demo

#Navigate to /.ssh folder

cd ./ssh

# Copy the new key to the end of this file

sudo nano authorized_keys

#preferable add a comment before copying the key, to ease deltion when required

Ex:
#alexmoss
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC02OIj1pBWlX7tynDEXXNMvmj37TfA+SLIhBc+o8SzDdkAmokgH43oQCgTKCY+f2HoVYK59UwwzUzPEo8QdY7ge4jiK/SH7R4PsNGi1LuWTkqiXWboFaUhSsiguKBJgr96PgDR3kZcvP3WxCdAxWGjGZe3Km9sW2zhF4Vw8sQ+hV/JhYjwEIOls7SgFVpgeoXZDCgVz78vrjTmTbJ6yfWN0KqiwUrSbRKLgFQsggWpmdjl5Ca+Y2Z6OGsAS3r2Mcs01jrb1LZPSIqBzJ6JToTyyMvUY2KsupSr0uQxSxkYwBrLmEDgQ6V7hJIY69j5njXrWRBZjaUAg/HsiCiEi5Kj [email protected]

3) Verify you are able to login with the new private key

ssh -i yourname [email protected]

You can then send the private key (christina to the user) . 
If the user is using windows etc and needs to convert the same to ppk, instructions can be found at http://support.cdh.ucla.edu/help/132-file-transfer-protocol-ftp/583-converting-your-private-key-

You can also do this conversion on your mac as follows:
puttygen christina -o christina.ppk -O private