Adding tzdata package to Alpine image
Adding tzdata package to Alpine image

When performing a `transaction` request n26 does some timestamp modification to make the timestamp relevant to the user's timezone. This operation requires certain files to be in place to resolve the "Europe/Berlin" timezone.  If they are absent [this issue](https://github.com/guitmz/n26/issues/26) arises.

On Alpine Image these files are provided by the `tzdata` package.  Adding this package in the n26 `Dockerfile` fixes the issue.
guitmz/n26