fix warning 'nohup: redirecting stderr to stdout' for resque.sh

Fix shared Redis connection issue on Passenger

Fix replace return with next in rake rask

related issue https://github.com/gitlabhq/gitlabhq/issues/2045

Fixed broken link to developer guide, fixes #2380

Update doc/install/installation.md

Better support for error handling in dev environment

'th -> the' typo

Changed wording if milestone already expired