adding stripe integration for charge

index.js

...
var stripeCharge = require('./stripeCharge.js')

...

app.post('/api/purchase', parseURLencoded, function(req, res) {
  var auth = req.headers['authorization']
  if (auth !== "false") {
    var token = req.body.token
    var amount = req.body.amount
    stripeCharge.charge(token, amount)
    res.status(201)
  } else {
    res.status(401).send("Unauthorized.")
  }
})

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