Allow users editing their membership dates.

But do not allow to change their status.
Add ability spec
Add test for group memberships set into the future
adding newrelic service.

website: http://newrelic.com/ruby
trello: https://trello.com/c/BVddSI1g/585-newrelic
newrelic: fixing configuration to import license key properly.
urls: adding the title to the url for Pages, Groups and Users.

railscast: http://railscasts.com/episodes/314-pretty-urls-with-friendlyid\?view\=asciicast
Prevent changes to ancestor_id and other integral values
Merge pull request #37 from fiedl/jr/531-berechtigungen-zur-corporatevita

Jr/531 berechtigungen zur corporatevita
adding flamegraph.

to view the flamegraph, just add the url parameter ?pp=flamegraph.