[Feature Request] Button in the popup to whitelist the current page (aka uBlock powerbutton ripoff)

[mwsundberg]

Is your feature request related to a problem? Please describe. Adding sites to the whitelist from #30 requires going to the extensions settings page and manually entering the domain every time.

Describe the solution you'd like A clear toggle or button to add the currently active tab's url to the domain whitelist. This won't be a 100% perfect solution for every site breakage (iframes on different domains loaded inside the active tab won't be put on the whitelist), but it's a happy medium that won't add unintended extra sites to the whitelist. Basically ripping off uBlock Origin's massive power button.

Additional context I plan to work on this soon but if someone else wants to have a go (feel free to, no ownership claimed!) they should probably wait until after the Bootstrap removal related refactoring (issue #45, PR pending) dust clears, a major rewrite of all popup code is coming with that.