Update working-with-associations.rst
Update working-with-associations.rst

As requested: https://github.com/doctrine/doctrine2/pull/6171#pullrequestreview-15695400
tPl0ch/doctrine2,tPl0ch/doctrine2,Ocramius/doctrine2,mikeSimonson/doctrine2,aivus/doctrine2,mikeSimonson/doctrine2,TomasVotruba/doctrine2,Ocramius/doctrine2,bigfoot90/doctrine2,TomasVotruba/doctrine2,Ocramius/doctrine2,stof/doctrine2,yurybykov/doctrine2,guiwoda/doctrine2,nicolas-grekas/doctrine2,doctrine/doctrine2,guiwoda/doctrine2,gencer/doctrine2,lcobucci/doctrine2,stof/doctrine2,beanworks/doctrine2,gencer/doctrine2,beanworks/doctrine2,Majkl578/doctrine2,aivus/doctrine2,localheinz/doctrine2,bigfoot90/doctrine2,lcobucci/doctrine2,nicolas-grekas/doctrine2,localheinz/doctrine2,deeky666/doctrine2,Sitetheory/doctrine2,deeky666/doctrine2,PowerKiKi/doctrine2,PowerKiKi/doctrine2,Majkl578/doctrine2,holtkamp/doctrine2,yurybykov/doctrine2,doctrine/doctrine2,holtkamp/doctrine2,Sitetheory/doctrine2