[Feature] Restore function

[Matsa59]

It could be nice to have a function to restore a soft deleted entity.

something like the following code sample in the file https://github.com/revelrylabs/ecto_soft_delete/blob/master/lib/ecto/soft_delete_query.ex

  def restore(query) do
    update(query, [t], set: [deleted_at: nil])
  end

[mithereal]

this wont work due to ecto casting nil to utc_datetime_usec raw query is required, fixed in pr #143

[Matsa59]

We have a functino restore/1 that works nicely

  def restore(struct) do
    struct
    |> Ecto.Changeset.change(%{deleted_at: nil})
    |> Repo.update()
  end

[mithereal]

hmmm i dont see it in the repo nor in the hex.docs, however when i try to nil a datestamp by running restore() as specified above in postgres ecto casts it to now(), i believe this is the default behaviour of ecto for date/time types as i see many discussions about it.

[Matsa59]

No I mean, we have added this function into our code ^^

I will continue this discussion your PR