Improve documentation for use with Ionic

[brodycj]

For example: #355 (comment) by @swastikpareek

I have recently upgraded my cordova version from 5.x.x to 6.x.x which was a break release (unfortunately) and openDB function which was initially taking database name as a whole and sole required parameter needed to have one more argument 'location' clubbed with database name as json ..

Due to this upgradation to break release my db var was getting a null value; and hence this problem.

So $cordovaSQLite.openDB("myapp9.db"); needed to be changed with $cordovaSQLite.openDB({name:"myapp9.db", location:'default'});

Changing this solved my problem.