Editing exisiting provider URLs #233

Hey!
First thing, I am really grateful for this application and loving it.

It would be nice if there was the ability to just manipulate a URL, since it is mostly human-readable and would be easier than adding a new URL and removing the old one.

Thanks for considering!

Ps.: I would be open to developing this little feature myself; it would be the first open source development ever tho :)