heroku pg:reset DATABASE
heroku run rake db:migrate
# If you have a seed
heroku run rake db:seed
Step 1: heroku restart
Step 2: heroku pg:reset DATABASE (no need to change the DATABASE)
Step 3: heroku run rake db:migrate
Step 4: heroku run rake db:seed (if you have seed)
One liner
heroku restart; heroku pg:reset DATABASE --confirm APP-NAME; heroku run rake db:migrate