run command from folder via cron

run command from folder via cron

I wrote this task for cron:
0 * * * * cd ~/projects/stat-eprorok-rails4/current && rvm use 2.0.0 do
bundle exec rake vk_posts:update_likes RAILS_ENV=production
I do not understand why the task is not performed every hour, because this
script works:
cd ~/projects/stat-eprorok-rails4/current && rvm use 2.0.0 do bundle exec
rake vk_posts:update_likes RAILS_ENV=production