title: How to set Currency Format in braintree transaction sale
body: <p>I create a APP in which i use Braintree Payment Gateway. In my application i make options to set different currency, am just know that how to set currency when i set sale transaction param.</p>
  
  <p>here is my code</p>
  
  <pre><code>$result = Braintree\Transaction::sale([
                      'amount' =&gt; '50.00',
                      'creditCard' =&gt; array(
                       'cardholderName' =&gt; 'Test Name',
                       'number' =&gt; '4000111111111511',
                       'expirationDate' =&gt; '12/2018',
                       'cvv' =&gt; '123',
                      ),
                      'options' =&gt; [ 'submitForSettlement' =&gt; true]
                ]);
  </code></pre>
  
  <p>All of my transaction made in US Dollar, but i want to make transaction in different currencies.</p>
  
  <p>Please someone give me the solution.
  thanks</p>