Persist Urns in raw bytes32 format

- Enables simple usage in contract storage lookups

pkg/transformers/vat_grab/converter.go

@@ -3,7 +3,6 @@ package vat_grab
 import (
 	"encoding/json"
 	"errors"
-	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/shared"
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/shared/constants"
@@ -20,10 +19,10 @@ func (VatGrabConverter) ToModels(ethLogs []types.Log) ([]interface{}, error) {
 			return nil, err
 		}
 		ilk := shared.GetHexWithoutPrefix(ethLog.Topics[1].Bytes())
-		urn := common.BytesToAddress(ethLog.Topics[2].Bytes())
-		v := common.BytesToAddress(ethLog.Topics[3].Bytes())
+		urn := shared.GetHexWithoutPrefix(ethLog.Topics[2].Bytes())
+		v := shared.GetHexWithoutPrefix(ethLog.Topics[3].Bytes())
 		wBytes := shared.GetDataBytesAtIndex(-3, ethLog.Data)
-		w := common.BytesToAddress(wBytes)
+		w := shared.GetHexWithoutPrefix(wBytes)
 		dinkBytes := shared.GetDataBytesAtIndex(-2, ethLog.Data)
 		dink := big.NewInt(0).SetBytes(dinkBytes).String()
 		dartBytes := shared.GetDataBytesAtIndex(-1, ethLog.Data)
@@ -35,9 +34,9 @@ func (VatGrabConverter) ToModels(ethLogs []types.Log) ([]interface{}, error) {
 		}
 		model := VatGrabModel{
 			Ilk:              ilk,
-			Urn:              urn.String(),
-			V:                v.String(),
-			W:                w.String(),
+			Urn:              urn,
+			V:                v,
+			W:                w,
 			Dink:             dink,
 			Dart:             dart,
 			LogIndex:         ethLog.Index,