app.coffee

module.exports = (app) ->
  r = app.redis
  db = app.db
  
  app.get '/', (req, res, next) ->
    res.render 'index'
  
  app.get '/foo', (req, res, next) ->
    res.render 'foo'

server.coffee

app = express.createServer
...


app.db = ...
app.redis = ...


require('./app')(app)


app.listen ...