Explore integration of UI widgets

[adamantivm]

Explore which widgets from other tools we're going to integrate (Trello, Google Docs, Github) can be integrated in the necessary perspective UIs and how.

Please add here any of the following:

• Tools that we know we might want to integrate, including any detail about which UI function we might need to integrate
• General information about experiences, ideas and tips on how to integrate UI widgets in our platform
• Particular tests/experiments done and their results / current state of exploration

If necessary, we can open sub-issues and reference them here.

[hughie]

We tried to show list of google drive documents and show the contents by iframe.
I don't like iframe. but, we don't have different way to provide similar functions as google drive.

It has expiration and quota issues. we will check about it.