root:*:					Super user, may do almost anything
security:*:				Security password for critical requests
system:<system>:		May add/delete powers, edit config files
mail:<mail>:			To work on mail messages in folders (from maildir)
list:<list>:			May perform administration on mailing lists
shell:*:				Shell clearance needed to execute shell commands
file:*:					File clearance needed to retrieve arbitrary files
