I have the following entry in crontab:
0 5 * * * /bin/bash -l -c \'export RAILS_ENV=my_env; cd /my_folder; ./script/my_script.rb 2>&1 > ./log/my_lo
Judging by this answer you just need to switch the order of the redirects:
0 5 * * * /bin/bash -l -c 'export RAILS_ENV=my_env; cd /my_folder; ./script/my_script.rb > ./log/my_log.log 2>&1'