Hello Vipin,
welcome on our community forum!
First, I would recommend you to upgrade to a more recent version (we are currently running 7.7 version of SonarQube…) as 5.01 is quite old.
You’ll find here the news of the release of 7.7 version which offers PR Decoration in BitBucket 
and official announcement here.
A quick point: to upgrade from 5.0 to newest version, you should follow the LTS path: 5.0–>5.6 LTS–> 6.7LTS and then 7.X version (next LTS should arrive before summer).
Enjoy the journey and new BitBucket integration
Carine