Offline mode - sources not showing up

[bricefriha]

Description 📜

I discovered this bug when working on #211.
The sources for articles don't seem to show up offline

To Reproduce ⚙

Steps to reproduce the behaviour:

1. Open the app once
2. Disable mobile data and wifi
3. Reopen the app

Expected behaviour 🕵🏼‍♀️

The sources should show up even when offline

Smartphone (please complete the following information):

• Device: All
• Version 1.6

Additional context ℹ

It seems to be to do with the SQLite service