Add fee to serialization

lib/transaction/transaction.js

@@ -239,6 +239,7 @@ Transaction.prototype.toObject = function toObject() {
   });
   return {
     change: this._change ? this._change.toString() : undefined,
+    fee: this._fee ? this._fee : undefined,
     version: this.version,
     inputs: inputs,
     outputs: outputs,
@@ -269,6 +270,9 @@ Transaction.prototype.fromObject = function(transaction) {
   if (transaction.change) {
     this.change(transaction.change);
   }
+  if (transaction.fee) {
+    this.fee(transaction.fee);
+  }
   this.nLockTime = transaction.nLockTime;
   this.version = transaction.version;
 };

test/transaction/transaction.js

@@ -245,6 +245,14 @@ describe('Transaction', function() {
         return transaction.serialize(true);
       }).to.not.throw();
     });
+    it('stores the fee set by the user', function() {
+      var fee = 1000000;
+      var serialized = new Transaction()
+        .fee(fee)
+        .toObject();
+      var deserialized = new Transaction(serialized);
+      expect(deserialized._fee).to.equal(fee);
+    });
   });
 
   describe('checked serialize', function() {