Document thor docs:download --all

README.md

@@ -30,7 +30,7 @@ bundle exec rackup
 
 Finally, point your browser at [localhost:9292](http://localhost:9292) (the first request will take a few seconds to compile the assets). You're all set.
 
-The `thor docs:download` command is used to download pre-generated documentations from DevDocs's servers (e.g. `thor docs:download html css`). You can see the list of available documentations and versions by running `thor docs:list`. To update all downloaded documentations, run `thor docs:download --installed`.
+The `thor docs:download` command is used to download pre-generated documentations from DevDocs's servers (e.g. `thor docs:download html css`). You can see the list of available documentations and versions by running `thor docs:list`. To update all downloaded documentations, run `thor docs:download --installed`. To download and install all documentation this project has available, run `thor docs:download --all`.
 
 **Note:** there is currently no update mechanism other than `git pull origin master` to update the code and `thor docs:download --installed` to download the latest version of the docs. To stay informed about new releases, be sure to [watch](https://github.com/freeCodeCamp/devdocs/subscription) this repository.