I really enjoy the Containers. The only problem is that you can only have a single container tied to an individual site. I'd rather like it to be tied to a subpath or url "root" so I could use it with GitHub.
I recommend the Search and Switch container[1] extension for that. You open a new tab, type 'co <container name' and it reloads that tab into the given container. For example, I have a container for all things Google, called "Google", and the extension use would go like this 'co google', or even 'co goo'. It's smart enough to figure it out.
Plus, you can also move existing tabs into a given container the same way, not just new tabs, all at the cost of a single tab refresh.