In Windows, and every permutation of Linux I've tried, you can pin a website as a icon shortcut to the dock / start menu / quick menu.
How can I do this in OSX? I use a habitica for my to-do list and I need a one-click entry to it all times
Okay I just found a way.
You have to drag the website from Firefox left-hand side of the URL bar to your desktop. It will make a new file.
Move it into a permanent location, like Documents. Then drag that to the RIGHT-side of the dock. It will pin. Oddly it won't let you arrange it in the order you want to. It must stay on the right.
But the only catch is you cannot delete the file in Documents. If you do, it'll just show a question mark when you click the pinned icon.