Ask HN:Launched a community for doctors, but..

We have just launched http://drlinked (Dr linked in) a community for doctors currently featuring a question answer platform(like stackoverflow) and news discussion platform(like hacker news). But we are stuck on finding users. Can you guys suggest me how should I proceed to find users. We are a two guys startup with zero funding, we want to get things moving forward any suggestions would be appreciated.

Thanks Rohith