title: plaid + stripe ach payment integration
body: <p>i'm integrate use plaid + stripe api to ach payment, but i can't get stripe_bank_account_token from plaid to call curl request after get account id and public_token</p>
  
  <p>i'm use php here is request</p>
  
  <pre><code>curl https://tartan.plaid.com/exchange_token \
     -d client_id="[Plaid client ID]" \
     -d secret="[Plaid secret]" \
     -d public_token="[Plaid Link public_token]" \
     -d account_id="[Plaid Link account_id]"
  </code></pre>
  
  <p>and response is { "sandbox": true, "access_token": "test_chase" }</p>
  
  <p>i can't get </p>
  
  <pre><code>{
    "sandbox": true,
    "access_token": "[Plaid API access token]",
    "stripe_bank_account_token": "btok_5gr1QIfvhgEKdYSr17rH",
    "account_id": "[Plaid Account ID]"
  }
  </code></pre>
  
  <p>this response </p>