Redirect after post show and login

[sseerrggii]

When you see a post and you are not logged in you see a button for login

After the login you should be redirected to this post show

http://community.coopdevs.org/t/redireccionar-al-entrar-por-post/29

[markets]

@enricostano I think this would be fixed by your changes in #249

[enricostano]

@markets could be 👍

[sseerrggii]

I reopen because it was not fixed, it is a important improvement for the user experience