Add port 3001 to docker port mapping

docs/cryptpad-docker.md

@@ -19,7 +19,7 @@ Run from the cryptpad source directory, keeping instance state in `/var/cryptpad
 
 ```
 docker build -t xwiki/cryptpad .
-docker run --restart=always -d --name cryptpad -p 3000:3000 \
+docker run --restart=always -d --name cryptpad -p 3000:3000 -p 3001:3001 \
 -v /var/cryptpad/files:/cryptpad/datastore \
 -v /var/cryptpad/customize:/cryptpad/customize 
 -v /var/cryptpad/blob:/cryptpad/blob \