<Link to={`readings/edit/${reading.id}`} params={{id: reading.id}}>

<Route path="/" component={App}>
        <IndexRoute component={Greetings}/>
        ...
        <Route path="readings/edit/:id" component={requireAuth(ReadingEdit)}/>
        <Route path="readings/:tab" component={requireAuth(ReadingListContainer)}/>
        ...
    </Route>