Setting database config params from config file in Sinatra

gistfile1.rb

DB_CONFIG = YAML.load(File.open('config/database.yml'))
EXCEPTIONS = ['[email protected]', '[email protected]']
LDAP = Ldap.setup

set :public_folder, 'public'
db_config = <<END
mysql2://#{DB_CONFIG['username']}:\
#{DB_CONFIG['password']}@#{DB_CONFIG['host']}:\
#{DB_CONFIG['port']}/#{DB_CONFIG['database']}
END
set :database, db_config