heroku not updating database schema
Do you see any output when you heroku rake db:migrate?
Try running heroku restart after you migrate to restart the web servers and DJ workers. That shouldn't influence your console, but I have seen web servers serving old versions of the code immediately after a deploy, which normally isn't a problem but with pending migrations can be.
You might want to try
heroku run rake db:migrate
heroku restart
Hope this helps.
The accepted answer is right. FYI though, you now use heroku run rake db:migrate because heroku rake db:migrate is deprecated