data Offer = Offer {
     name :: Text
   , description Text
   , supplier :: SupplierId
   , category :: CategoryId
   , tags :: [TagId] 
   , images :: [Image]
   , variants :: [Variant]
   , active :: Bool
}

offer <- runJSONForm $ Offer <$> ireq textField "name"
                             <*> ireq textField "description"
                             <*> ireq jsonField "supplier" 
                             <*> ireq jsonField "category")
                             <*> ireq jsonField "tags")
                             <*> ireq jsonField "images"
                             <*> (fmap nub $ ireq jsonField "variants")
                             <*> ireq boolField "active"