Set up iTerm to delete whole words on Option-Backspace

Out of the box, on a fresh iTerm2 installation when you press Option-Backspace (⌥ ⌫) it won't delete whole words but instead backspace delete one character at a time.

The solution is to

1. Open iTerm2's settings by pressing ⌘ ,
2. Go to Profiles
3. Select "Keys" tab
4. Look for "Left option (⌥) key:"
5. Change it from "Normal" to "Esc+"
6. Close the preferences window

I keep forgetting this and struggled to find up-to-date instructions so hopefully by blogging about it I won't forget next time.