Add gitbook init command to "how to use" section

Highlight that Gitbook can generate the files and directories for a book from its SUMMARY.md file.

1 files changed, 5 insertions, 0 deletions

diff --git a/README.md b/README.md
index a164c3f..dcf974b 100644
--- a/README.md
+++ b/README.md
@@ -16,6 +16,11 @@ GitBook can be installed from **NPM** using:
 $ npm install gitbook -g
 ```
 
+Create the directories and files for a book from its [SUMMARY.md](https://github.com/GitbookIO/gitbook#book-format) file using 
+```
+$ gitbook init
+```
+
 You can serve a repository as a book using:
 
 ```