!set_prefix command is deleting network in config.json

[JohnGarnham]

When a user calls set_prefix and changes the prefix, when it updates config.json with the new prefix it is not keeping the network setting. Which means that the network gets wiped out whenever the command prefix is changed. Error is in:

                // Read in new prefix
                var newPrefix = args[0];
                // Create new config
                var newConfig = {
                    token: oldConfig.token,
                    prefix: newPrefix,
                };
                // Write new config 
                try {
                    fs.writeFileSync("config.json", JSON.stringify(newConfig, null, 2), function(err, result) {
                        if (err) throw err;
                    });
                } catch(e) {
                    // Error updating config file
                    console.error("Error writing new config.json: " + e);
                    console.error(e.stack);
                    message.channel.send("Could not set new command prefix: " + e);
                }