Refactor this app to support multiple poster groups with own configuration

aleksis/apps/resint/admin.py

aleksis/apps/resint/default.odt

aleksis/apps/resint/default.pdf

aleksis/apps/resint/forms.py

aleksis/apps/resint/menus.py

aleksis/apps/resint/migrations/0001_initial.py

aleksis/apps/resint/models.py

aleksis/apps/resint/settings.py

aleksis/apps/resint/templates/resint/group/create.html

aleksis/apps/resint/templates/resint/group/edit.html

aleksis/apps/resint/templates/resint/group/list.html

aleksis/apps/resint/templates/resint/index.html

aleksis/apps/resint/templates/resint/poster/list.html

aleksis/apps/resint/templates/resint/poster/upload.html

aleksis/apps/resint/templates/resint/upload.html

aleksis/apps/resint/urls.py

aleksis/apps/resint/views.py