In this write up I will describe how to create a custom Chromebok/Chrome OS app. I can't take full credit info was obtained from http://www.omgchrome.com. Just thought it would be good info to share and may the instructables crew would actually want to make a Chrome app available in the web store.
Step 1: Set Up
Create a folder on your Chromebook, name the folder after your web app. In this example I’m naming it ‘Instructables' because I’m creating a Instructables web app.
Step 2: Create Web App Icon
In this folder, download/create an icon for the app (it needs to be a 128×128 PNG file), rename it “icon_128.png”.
Step 3: Code the App
Now you’ll need to create a plain text file with the following contents. Rename/edit the contents as per your web app.
"description": "App description (132 characters or less, no HTML)",
Step 4: Rename Txt File
Saved the file, renaming it to “manifest.json” (make sure the .txt file extension is gone).
Step 5: Enable Chromebook to Test App
Once you have the icon and json file in the folder you should test that it works.
Open the ‘Extensions’ page from Chrome’s Settings menu. Tick “Developer Mode”. Click “Load Unpacked Extension” and select the web app folder.
The Web App should now be installed on your New Tab page.
Step 6: See You App in Action and Notes!
Please note, you can not delete the web app folder, since Chrome will load the web app from this folder.
To publish your web app to the Chrome Web Store you will need to be the owner of the domain used by the web-app. If you do not own the domain of the web app, you can not publish it to the Chrome Web Store.