Add package-lock.json and update README (#32)

Author: jbagga

.gitignore

@@ -1,2 +1,3 @@
 bower_components/
-node_modules/
+node_modules/
+*.nupkg

README.md

@@ -5,3 +5,6 @@ The jQuery Unobtrusive Ajax library complements jQuery Ajax methods by adding su
 
 This project is part of ASP.NET Core. You can find samples, documentation and getting started instructions for ASP.NET Core at the [Home](https://github.com/aspnet/home) repo.
 
+Remember to make your changes to only the src file. Use ".\build.cmd" to automatically generate the js file in dist directory, minify the js file, create a .nupkg and change the version in the package.json if needed.
+
+To stage for a release, update the "version.props" file and run ".\build.cmd" (see ReleaseNotes [here](https://github.com/aspnet/jquery-ajax-unobtrusive/wiki/Release-checklist)).