Access denied

Hi All

i have run this program. i got this error

Access denied for user 'root'@'localhost' (using password: NO)

i am using mysql db.

below database.yml

# Install the MySQL driver:
# gem install mysql
# On MacOS X:
# gem install mysql -- --include=/usr/local/lib
# On Windows:
# gem install mysql
# Choose the win32 build.
# Install MySQL and put its /bin directory on your path.


did u reboot your server once u modified the database.yml file?