Where can I publish the draft paper of my masters thesis?
The thing to do is to check your target journal's submission guidelines: what you're looking for, is their attitude to preprints - a preprint is a draft of an journal article, made and distributed before publication.

If they're happy that preprints do not constitute prior publication, you can submit a preprint to a suitable archive (making sure you get the permission of your co-authors first), and this will help establish your precedence.

In the case of your target journal, the "how to submit" page says:


  Posting a manuscript on a pre-print server such as ArXiv or SSRN is not considered to be duplicate publication.


So in this case you're ok to submit your draft article to a preprint archive, to establish that this is your work and not your supervisor's, and it won't damage your chances of getting published in your target journal.

We have a number of other questions about preprints, and you might find lots of useful related information on the answers there.