Timestamp is incorrect when a user joins the queue

[alexanderl19]

Expected Behavior

The server returns the current UNIX time in ms.

Current Behavior

The server returns a time that is seemingly random.

Possible Solution

Change System.nanoTime() to System.currentTimeMillis()

https://github.com/UB-CSE/OfficeHours/blob/develop/src/main/scala/model/OfficeHoursServer.scala#L63

class EnterQueueListener(server: OfficeHoursServer) extends DataListener[String] {
  override def onData(socket: SocketIOClient, username: String, ackRequest: AckRequest): Unit = {
>>>>server.database.addStudentToQueue(StudentInQueue(username, System.nanoTime()))<<<<
    server.socketToUsername += (socket -> username)
    server.usernameToSocket += (username -> socket)
    server.server.getBroadcastOperations.sendEvent("queue", server.queueJSON())
  }
}

Steps to Reproduce

1. Click the join queue button a few times
2. Look at the time stamps in the waiting list
3. Convert time stamps from UNIX to human time

Context (Environment)

It is important to see when people have queued.
This information could help give an estimate of how long someone would have to wait before they queue or it could indicated that the TA's can not keep up with the demand.

Detailed Description

According to https://docs.oracle.com/javase/8/docs/api/java/lang/System.html, System.nanoTime() returns the Returns the current value of the running Java Virtual Machine's high-resolution time source, in nanoseconds., not the current UNIX time.