Add Vaadin Cookbook under Building Apps

Author: veerapaananen

articles/building-apps/cookbook.adoc

@@ -0,0 +1,19 @@
+---
+title: Cookbook
+page-title: Vaadin Cookbook | Code snippets for common tasks
+description: Code snippets for common tasks
+meta-description: A collection of solutions to common use cases you run into when developing business web applications with Vaadin.
+order: 50
+---
+
+
+= Vaadin Cookbook
+
+[IMPORTANT]
+Some solutions in the Cookbook might be not use the current best practices.
+
+https://cookbook.vaadin.com/[Vaadin Cookbook] is a collection of solutions to common use cases you run into when developing business web applications with Vaadin.
+
+Solutions are implemented using Java, TS or a mix that is appropriate. The focus is on the solution, not how it is implemented.
+
+https://cookbook.vaadin.com/[Open Cookbook, role="button primary water"]