simplify controllers the rails way. details missing

flash_for:
  The idea is to have a tool that is similar to respond_with - but for flash messages.
  It should detect the action and wether it was successful.
  And then it should fetch the proper message from i18n and display it if present.

respond_with removed:
  There's no need for it if we only respond_to :html.

authorize when fetching data:
  This way we make sure no group is loaded without calling authorize on it afterwards.
add group creation form to group list
minor: style tweaks to columns - 3 in a row
groups with description, membership, actions_for(group)
use a fairly generic directory view
initial use of draper decorators
made quite a bit of progress with gneeric action helpers using pundit and draper.

Some things are still missing . In particular a link_to form for memberships.
allow creating memberships with action magic
move list of actions into view and cleanup some
structure not markup in main haml template

moving actions into the decorator again.
define actions in ActionFactory context

use method_missing to still be able to access properties of the context