Heroku deployment with MongoDB database

Currently, I develop a Rails app with mongodb as the database.
When I decided to deploy this in heroku, as per the heroku dev doc, I was asked to simply install the MongoHQ Add-on, and specify the plan that I desire.

So, supposedly all I had to do was this,

heroku addons:add mongohq:small

and I would have the MONGOHQ_URL to add to the mongoid configuration ( config/mongoid.yml ).
But unfortunately, this would ask me to verify my heroku account

Adding mongolab on chillrapi... failed ! Please verify your account to install this add-on ! For more information, see http://devcenter.heroku.com/categories/billing ! Verify now at https://heroku.com/verify

Clicking on the verification link asks for my credit card details. Now, its mentioned that mongohq-small is a free version of the add on. So you could probably carry on providing your details. For the others, you may please read on.

MongoHQ is a cloud-based hosted database solution that allows developers to easily deploy, manage and scale both single and replica set MongoDB databases for their web and mobile applications.

I created a new database (SandBox, 512 MB - thats all I needed anyways ) at MongoHQ.
On creating a new database, MongoHQ provides us with a mongo console and mongo uri connection strings.

Mongo Console
mongo paulo.mongohq.com:10097/chillr_db -u <user> -p<password>

Mongo URI

Now, add a database user with a username, password. Check mongohq support docs for reference.

You could try out the mongo console connection string from your local to check if the user credentials are valid. Once you find them valid, add the MONGOHQ_URL to the heroku config set.

heroku config:set MONGOHQ_URL="mongodb://<user>:<password>@paulo.mongohq.com:10097/chillr_db"

Be sure to replace the username and password while adding.
Thats it, Mongodb hosted in MongoHQ should be now available for use in the application.