Added friendly_networks variable to denote whitelisted networks

.gitignore contained complete path to /vars/user.yml but we want to ignore the
locale version inside local vars directory

That way we can override all the config from a central location. The
`user.yml` file overrides `defaults.yml`. `user.yml` was added to
`.gitignore` in order to allow a user to change it without having to
worry about merges. It's easy to do a diff to see what changed between
the defaults and your own settings.

Needs documentation, this is just a proposal.

Refs #39