Update index.md

This seems to be the right thing. I follow this format:
{
    name: 'media',
    value: 'org.apache.cordova.media',
    uri: 'https://github.com/apache/cordova-plugin-media.git#r0.2.14',
    version: '0.2.14',
    default: false 
}
Merge pull request #5 from srenault/patch-1

Fix documentation about adding your own plugin