fix problem with broken reference to thumbnail model
fix problem with broken reference to thumbnail model

Kachachan/musicblocks,sneh1234/musicblocks,pikurasa/musicblocks,sneh1234/musicblocks,pikurasa/musicblocks,hemantkasat/musicblocks,tradzik/musicblocks,pikurasa/musicblocks,hemantkasat/musicblocks,tradzik/musicblocks,khandelwalYash/musicblocks-1,Kachachan/musicblocks,khandelwalYash/musicblocks-1,sneh1234/musicblocks,hemantkasat/musicblocks,Kachachan/musicblocks,tradzik/musicblocks,khandelwalYash/musicblocks-1