code: func (a *Application) AddCommand(command Command) {
  	a.Commands = append(a.Commands, command)
  
  	newCmd := &a.Commands[len(a.Commands)-1]
  	if newCmd.Group != "" {
  		group := a.groupByName(newCmd.Group)
  		if group == nil {
  			panic("group doesn't exist")
  		}
  
  		group.Commands = append(group.Commands, newCmd)
  	} else {
  		a.ungroupedCmdsCount++
  	}
  }
docs: // AddCommand does literally what its name says.