rename admin to administration to avoid name clash
move signal registration to AppConfig
avoid recursive imports
define models for Podcasts, Episodes
get random podcasts from PostgreSQL

get_logo_url moved from Podcast/PodcastGroup to mygpo.web.logo.get_logo_url()
use unicode_literals in models, admin
allow last_update=None to indicate no update yet
set Podcast.episode_count=0 by default
update model Meta classes
update schema migrations
require Django 1.7 (currently Beta 4)
allow slugs to to 150 chars
require custom fix of benoitc/couchdbkit#180
use PostgreSQL db during Travis CI tests
enable django.contrib.{auth,admin}
delete unused management cmd move-subscriber-data
get podcast count from PostgreSQL
re-enable django_couchdb_utils.couchauth
get podcats languages from PostgreSQL
get podcast licenses from PostgreSQL