lib/classes/PluginManager.js/PluginManager/loadCommands
class PluginManager:  loadCommands(pluginInstance) {
    const pluginName = pluginInstance.constructor.name;
    _.forEach(pluginInstance.commands, (details, key) => {
      const command = this.loadCommand(pluginName, details, key);
      this.commands[key] = _.merge({}, this.commands[key], command);
    });
  }