Bug: `Custom Rules` button forwards to an empty page

[mateobelanger]

Hello!

First of all, let me say I love this project's simple and clean features.

Description of the issue

The Custom Rules sub-button links to http://localhost:14400/settings/rules which was (I think) removed in cli v0.3.0.

To note that the Extension Preferences button is also inactive.

[rphovley]

Thank you for the support @mateobelanger and great find! if you are interested, feel free to fix!