This is a demonstration of Office 365 Patterns and Practices code, which shows how you can surface your apps using a app dialog model where app is shown in modal dialog for example in the context of the host web. This demo shows three different things.
- How to use App popup or dialog
- How to add custom action to host web
- How to provision additional elements to host web
Actual code and additional details can be found from following address - https://github.com/OfficeDev/PnP/tree/dev/Scenarios/Provisioning.SiteModifier