forwarder.js

var CHANNEL_ID = "PUT_THE_CHANNEL_ID_HERE";
var FORMAT = "**User:** %user%\n**Message:** %message%";

var content = message.getContent();
var spaceFound = content.indexOf(" ");
if(spaceFound < 0) {
  channel.message("Please provide a message.");
  return;
}
var toForward = content.substring(spaceFound).trim();
toForward = FORMAT.replace("%user%", "<@" + user.getID() + ">").replace("%message%", toForward);
if(toForward.length() > 2000) {
  toForward = toForward.substring(0, 2000);
}
var target = guild.getTextChannel(CHANNEL_ID);
if(target == null) {
  channel.message("Invalid setup. Contact a server administrator.");
  return;
}
target.message(toForward);
channel.message("The message has been forwarded.");