Document/Provide preferences file for automatic upgrades for of leap packages

at https://dl.bitmask.net/linux/, we document the steps how to configure the leap repository. but without a dedicated /etc/apt/preferences.d/leap file like this:

Package: *
Pin: release o=leap.se 
Pin-Priority: 1000

packages that are provided by debian/ubuntu too would not get automatically updated from the leap repo.

i.e. the libzmq3 package:

without a preference file, it looks like this:

 apt-cache policy libzmq3
libzmq3:
  Installed: 4.0.4+dfsg-2
  Candidate: 4.0.4+dfsg-2
  Version table:
     4.0.4+leap-2+0~20140813002149.8+trusty~1.gbpc7a23b 0
        500 http://deb.bitmask.net/debian/ trusty/main amd64 Packages
 *** 4.0.4+dfsg-2 0
        970 http://archive.ubuntu.com/ubuntu/ trusty/universe amd64 Packages
        -10 http://de.archive.ubuntu.com/ubuntu/ utopic/universe amd64 Packages
        100 /var/lib/dpkg/status

with a preference file:

root@rocinante:/etc/apt/preferences.d# apt-cache policy libzmq3
libzmq3:
  Installed: 4.0.4+dfsg-2
  Candidate: 4.0.4+leap-2+0~20140813002149.8+trusty~1.gbpc7a23b
  Version table:
     4.0.4+leap-2+0~20140813002149.8+trusty~1.gbpc7a23b 0
       2000 http://deb.bitmask.net/debian/ trusty/main amd64 Packages
 *** 4.0.4+dfsg-2 0
        970 http://archive.ubuntu.com/ubuntu/ trusty/universe amd64 Packages
        -10 http://de.archive.ubuntu.com/ubuntu/ utopic/universe amd64 Packages
        100 /var/lib/dpkg/status

micah, as you are the master of debian packages, could you share your opinion pls ?

(from redmine: created on 2014-08-26, closed on 2014-11-11, relates #6021 (closed), relates #6306 (closed), relates #6301 (closed))