Store time when gather is completed

lib/gather/gather.js

@@ -31,6 +31,9 @@ function Gather (options) {
 		startTime: null,
 		timer: null
 	};
+	this.done = {
+		time: null
+	};
 	this.initState();
 }
 
@@ -132,6 +135,7 @@ StateMachine.create({
 
 		// On enter done
 		onenterdone: () => {
+			this.done.time = new Date();
 			this.onDone.call(this);
 		}
 	}
@@ -292,6 +296,9 @@ Gather.prototype.toJson = () => {
 		election: {
 			startTime: this.electionStartTime(),
 			interval: this.election.INTERVAL
+		},
+		done: {
+			time: this.done.time
 		}
 	}
 };