Update clone command for shallow submodules

README.md

@@ -2,7 +2,7 @@
 
 This is a template repository to bootstrap your documentation site with Hugo-Book theme. It contains minimal configured from the start hugo site.
 1. To use this repository create a new repository from this template
-2. Run `git clone --recurse-submodules https://github.com/{org/user}/{repository}`
+2. Run `git clone --recurse-submodules --shallow-submodules https://github.com/{org/user}/{repository}`
 3. Enter newly created directory `cd {repository}`
 4. Run hugo `hugo server`