fix/ remove yarn because of error with module dep in prod builds

Author: maximegris

README.md

@@ -36,12 +36,14 @@ Clone this repository locally :
 git clone https://github.com/maximegris/angular-electron.git
 ```
 
-Install dependencies with your favorite dependencies manager (npm or yarn) :
+Install dependencies with npm :
 
 ``` bash
 npm install
 ```
 
+There is an issue with `yarn` and `node_modules` that are only used in electron on the backend when the application is built by the packager. Please use `npm` as dependencies manager.
+
 If you want to generate Angular components with Angular-cli , you **MUST** install `@angular/cli` in npm global context.  
 Please follow [Angular-cli documentation](https://github.com/angular/angular-cli) if you had installed a previous version of `angular-cli`.