Fix #42 -  sortable column must be named position
Fix #42 -  sortable column must be named position

nlzet/SonataDoctrineORMAdminBundle,nlzet/SonataDoctrineORMAdminBundle,rmzamora/SonataDoctrineORMAdminBundle,pulzarraider/SonataDoctrineORMAdminBundle,mweimerskirch/SonataDoctrineORMAdminBundle,rschumacher/SonataDoctrineORMAdminBundle,aurelien-vtech/SonataDoctrineORMAdminBundle,nlzet/SonataDoctrineORMAdminBundle,Bladrak/SonataDoctrineORMAdminBundle,rschumacher/SonataDoctrineORMAdminBundle,EmmanuelVella/SonataDoctrineORMAdminBundle,aitboudad/SonataDoctrineORMAdminBundle,rschumacher/SonataDoctrineORMAdminBundle,pulzarraider/SonataDoctrineORMAdminBundle,sonata-project/SonataDoctrineORMAdminBundle,aurelien-vtech/SonataDoctrineORMAdminBundle,rmzamora/SonataDoctrineORMAdminBundle,nlzet/SonataDoctrineORMAdminBundle,rmzamora/SonataDoctrineORMAdminBundle,aurelien-vtech/SonataDoctrineORMAdminBundle,rschumacher/SonataDoctrineORMAdminBundle,pulzarraider/SonataDoctrineORMAdminBundle