Fire up firefox and download the RESTClient Add-on.
Window -> Add-ons Manager
Search -> RESTClient
Method:
POST
URL:
http://ec2-184-73-40-56.compute-1.amazonaws.com/sessions.json
Headers:
Content-Type: application/json
Body:
{
"user":
{
"email": "your@emailaddress.com", "password": "Your_Password"
}
}