heroku restart -a APP_NAME
heroku pg:reset -a APP_NAME DATABASE --confirm=APP_NAME
heroku run rake db:migrate -a APP_NAME
heroku run rake db:seed -a APP_NAME
One liner:
heroku restart -a APP_NAME; heroku pg:reset -a APP_NAME DATABASE --confirm=APP_NAME; heroku run rake db:migrate -a APP_NAME; heroku run rake db:seed -a APP_NAME