Add test for old expiresAt date in integration

cmd/web/main_integration.go

@@ -173,6 +173,22 @@ func runCreateElectionTests() {
   "choices": [
     "Gandhi"
   ]
+}`),
+		Expect().Status().Equal(http.StatusUnprocessableEntity),
+	)
+
+	MustDo(
+		template,
+		Send().Body().String(`
+{
+  "name": "Guy of the year",
+  "tokens": 100,
+  "areVotersKnown": false,
+  "maxVoters": 10,
+  "expiresAt": "2018-12-31T14:15:22Z",
+  "choices": [
+    "Gandhi"
+  ]
 }`),
 		Expect().Status().Equal(http.StatusUnprocessableEntity),
 	)