readme update for completeness

[daver208]

settings.redis.db = 10;
updateConfig(settings, './config/app.yaml', 'production'); //Save 10 to redis.db of the 'production' section
updateConfig({},'./config/app.yaml', 'production'); //Will remove the entire 'production' section

Should Likely be updated to:

var config = require('yaml-config');
var settings = config.readConfig('./config/app.yaml', 'production');
console.log(settings.redis.db); // prints 12
settings.redis.db = 10;
config.updateConfig(settings, './config/app.yaml', 'production'); //Save 10 to redis.db of the 'production' section
config.updateConfig({},'./config/app.yaml', 'production'); //Will remove the entire 'production' section