add user totalSales and totalOrders (#333)

schema.graphql

@@ -281,6 +281,12 @@ type User @entity {
   poolTransactions: [PoolTransaction!] @derivedFrom(field: "user")
   orders: [Order!] @derivedFrom(field: "payer")
   freSwaps: [FixedRateExchangeSwap!] @derivedFrom(field: "by")
+  
+  "total number of orders made by this user"       
+  totalOrders: BigInt!
+
+  "total number of orders made on assets owned by this user"       
+  totalSales: BigInt!
 }
 
 type FixedRateExchange @entity {

src/mappings/erc20Templates.ts

@@ -38,6 +38,8 @@ export function handleOrderStarted(event: OrderStarted): void {
   order.consumer = consumer.id
 
   const payer = getUser(event.params.payer.toHex())
+  payer.totalOrders = payer.totalOrders.plus(integer.ONE)
+  payer.save()
   order.payer = payer.id
 
   order.amount = weiToDecimal(
@@ -66,6 +68,9 @@ export function handleOrderStarted(event: OrderStarted): void {
       nft.orderCount = nft.orderCount.plus(integer.ONE)
       nft.save()
     }
+    const owner = getUser(nft.owner)
+    owner.totalSales = owner.totalSales.plus(integer.ONE)
+    owner.save()
   }
 }