Update README.md

README.md

@@ -8,7 +8,7 @@ This contains development tools for creating .pot files.
 * Copy and rename ```vendor/mapkyca/known-language-tools/Sample.Gruntfile.js``` to ``` ./Gruntfile.js ```
 * Copy and rename ```vendor/mapkyca/known-language-tools/Sample.package.json``` to ``` ./package.json ``` and edit accordingly
 * Make a ``` ./languages ``` directory in your project
-* Install grunt, and its dependencies (usually ``` npm install ```)
+* Install grunt, and its dependencies (usually ``` npm install --only=dev ```)
 * ``` grunt build-lang ```
 
 ## See