fix(model): handle mongoose models without caster option
fix(model): handle mongoose models without caster option

tothandras/graffiti-mongoose,hardchor/graffiti-mongoose,relax/graffiti-mongoose,RisingStack/graffiti-mongoose,nodkz/graffiti-mongoose,relax/graffiti-mongoose,parkan/graffiti-mongoose,brysgo/graffiti-mongoose,relax/graffiti-mongoose