add swap.from EOA

Author: ianlapham

schema.graphql

@@ -196,6 +196,7 @@ type Swap @entity {
 
   # populated from the Swap event
   sender: Bytes!
+  from: Bytes! # the EOA that initiated the txn
   amount0In: BigDecimal!
   amount1In: BigDecimal!
   amount0Out: BigDecimal!

src/mappings/core.ts

@@ -488,6 +488,7 @@ export function handleSwap(event: Swap): void {
   swap.amount0Out = amount0Out
   swap.amount1Out = amount1Out
   swap.to = event.params.to
+  swap.from = event.transaction.from
   swap.logIndex = event.logIndex
   // use the tracked amount if we have it
   swap.amountUSD = trackedAmountUSD === ZERO_BD ? derivedAmountUSD : trackedAmountUSD