Automatically trade the mapped asset

[DerekMelchin]

Expected Behavior

If we pass the continuous Future Symbol to the set_holdings method, it trades the mapped contract.

Actual Behavior

It throws

Backtest Handled Error: 2021-06-18 07:00:00 The security with symbol '/GC' is marked as non-tradable.

Potential Solution

N/A

Reproducing the Problem

https://www.quantconnect.cloud/backtest/d91cef26bd0baeed213a40972e3a42d2/?theme=darkly

System Information

QC Cloud

Checklist

• I have completely filled out this template
• I have confirmed that this issue exists on the current master branch
• I have confirmed that this is not a duplicate issue by searching issues

• I have provided detailed steps to reproduce the issue