To begin, you'll need to register a tumblr application.
create the file config/local.js an place your keys there. You can overwrite any of the config variables in config/base.js in this file. It's not checked into version control.
module.exports = {
CONSUMER_KEY: '89has87dhasdd9878hawd87h872387dw2'
, CONSUMER_SECRET: '87ahsd8uhd782h3ef87h45783ghw9efj29e87fh2'
};