Passing parameters to transactions

  collections: { 
    write: "users",
    read: [ "c1", "c2" ]
  },
    var db = require('@arangodb').db;
    var doc = db.c1.document(params['c1Key']);
    db.users.save(doc);
    doc = db.c2.document(params['c2Key']);
  params: { 
    c1Key: "foo", 
    c2Key: "bar" 
});