Added fixtures-hint to README
Added fixtures-hint to README

KonstantinBY/sonata-sandbox,KonstantinBY/sonata-sandbox,sonata-project/sandbox,EmmanuelVella/sandbox,4devs/sonata-sandbox,zsamotsil/polcode_task,KonstantinBY/sonata-sandbox,davask/exim-cms,EmmanuelVella/sandbox,morilog/sandbox,4devs/sonata-sandbox,Soullivaneuh/sonata-sandbox,tophsic/sandbox,gabrielalmeida/sonata-sandbox,4devs/sonata-sandbox,gabrielalmeida/sonata-sandbox,vihuvac/sandbox,JoshuaEstes/sonata-skeleton,OskarStark/sandbox,davask/exim-cms,nlzet/sandbox,nlzet/sandbox,zsamotsil/polcode_task,volodymyr-nakvasiuk/sandbox,Soullivaneuh/sonata-sandbox,tophsic/sandbox,tworzenieweb/polcode-recruitment,davask/exim-cms,volodymyr-nakvasiuk/sandbox,cbastienbaron/sandbox,cbastienbaron/sandbox,tophsic/sandbox,morilog/sandbox,morilog/sandbox,volodymyr-nakvasiuk/sandbox,rzproject/sandbox,sonata-project/sandbox,davask/exim-cms,tworzenieweb/polcode-recruitment,gabrielalmeida/sonata-sandbox,rzproject/sandbox,JoshuaEstes/sonata-skeleton,vihuvac/sandbox,nlzet/sandbox,rzproject/sandbox,volodymyr-nakvasiuk/sandbox,vihuvac/sandbox,OskarStark/sandbox,KonstantinBY/sonata-sandbox,Soullivaneuh/sonata-sandbox,vihuvac/sandbox,4devs/sonata-sandbox,Soullivaneuh/sonata-sandbox,sonata-project/sandbox,cbastienbaron/sandbox,morilog/sandbox,cbastienbaron/sandbox,OskarStark/sandbox,JoshuaEstes/sonata-skeleton,tophsic/sandbox