syntax error on line 18, col 2: ` socket: /tmp/mysql.sock'

[William Wright]

OK so Im a newbie with MySQL so please be nice :) I'm learning to use Ruby and MySQL and am going through the lynda.com training for Ruby. I am the part where I run rake db:migrate, and I get this error

williams-computer:/usr/local/src/music_library william$ rake db:migrate
(in /usr/local/src/music_library)
rake aborted!
syntax error on line 18, col 2: ` socket: /tmp/mysql.sock'

(See full trace by running task with --trace)

Can anyone help with this. I cannot go any further until this is corrected. In the tutorial the teachers yml file says host: localhost where mine says socket: /tmp/mysql.sock'. So I replaced it with host: localhost and got the same error.

Thanks,
William