suggestion: document pillar logic

[shawnbutts]

it would be helpful to have some examples of logic in the pillar file.

i.e. adding a user to only one host, enabling sudo for a user on only some hosts, etc.

[erchn]

Agreed on the logic suggestions. From what I can see there is no way to enable sudo on only one host, without more templating in the pillar file.

I'm also not quite clear how I should apply the pillar data to a given node, along with 'buser' and 'cuser', but not have to duplicate the data for application to another node which shouldn't have the b and c users.

[wwentland]

@shawnbutts You might be interested in https://github.com/saltstack-formulas/reverse-users-formula that allows user definitions in a user/hosts rather than host/users manner.