### Issue details

Please provide issue details here.
Remember, this is _not_ a place to ask questions. For that, go to http://gitter.im/wallabag/wallabag.

### Environment

* wallabag version (or git revision) that exhibits the issue:
* How did you install wallabag? Via `git clone` or by downloading the package?
* Last wallabag version that did not exhibit the issue (if applicable):
* php version:
* OS:
* type of hosting (shared or dedicated):
* which storage system you choose at install (SQLite, MySQL/MariaDB or PostgreSQL):

### Steps to reproduce/test case

Please provide necessary steps for reproduction of this issue, or better the
reduced test case (without any external dependencies, if possible).
