Add initial structure Coordinator Forge Sequence

common/errors.go

@@ -7,3 +7,6 @@ var ErrNotInFF = errors.New("BigInt not inside the Finite Field")
 
 // ErrNumOverflow is used when a given value overflows the maximum capacity of the parameter
 var ErrNumOverflow = errors.New("Value overflows the type")
+
+// ErrBatchQueueEmpty is used when the coordinator.BatchQueue.Pop() is called and has no elements
+var ErrBatchQueueEmpty = errors.New("BatchQueue empty")

common/zk.go

@@ -54,3 +54,7 @@ type ZKInputs struct {
 	OldKey2   []*big.Int
 	OldValue2 []*big.Int
 }
+
+type CallDataForge struct {
+	// TBD
+}