Check the example config.rb as recommended on the repo's README.
As shown there:
# Redirect STDOUT and STDERR to files specified. The 3rd parameter
# (“append”) specifies whether the output is appended, the default is “false”.
stdout_redirect '/u/apps/lolcat/log/stdout', '/u/apps/lolcat/log/stderr'
stdout_redirect '/u/apps/lolcat/log/stdout', '/u/apps/lolcat/log/stderr', true