Thank you @TanakaM for extending helpHi,
If you get a reference letter from the company that is all you will need. You can add the relieving letter as it is, but there is no need for a letter from your supervisor.
Here is a sample: http://www.canadavisa.com/canada-immigration-discussion-board/threads/nail-the-challenge-of-getting-reference-letter-from-current-employer.397796/#post-4972228
All the best