Put all of the ingredients into your slow cooker and stir and put on high for 4 hours or low for 8 hours.
Once it is cooked, shred the beef using 2 forks.
Notes
Slow cookers all cook things at different rates. You want to make sure that you don't overcook your beef as it will dry out. The beef is cooked when it easily shreds with a fork.
If you like your food with a real kick of heat, add some extra red chilli flakes.
If there is a lot of juice in your slow cooker after you take the joint out to shred, then you might want to remove some of the mixture before putting the shredded meat back in.
For something different, but really easy, mix the beef with BBQ sauce rather than the stock.