%3f URL --> '?'拼接引发的问题

ok, so I have an API that I built using ruby on rails. Pagination works completely in both the website and the API. Here is the api: https://sheltered-shelf-7331.herokuapp.com/api/yaks?page=1

just change out "page=1" at the end for "page=2" or "3", etc, and you‘ll see it works.

the problem though is that the "?" is read by the URL request as "%3F". Here is how the url request is printed in the console in Xcode:

  URL: https://sheltered-shelf-7331.herokuapp.com/api/yaks%3F 

So of course it has a response of html status code 404. How can I make the question mark not be converted to %3F in the URL? I‘m using URLRequest Convertible. Here is my code:

static let baseURL = "https://sheltered-shelf-7331.herokuapp.com"
let result: (path: String, parameters: [String: AnyObject]?) = {

        switch self {
        case GetMainFeed:
            return ("/api/yaks?", nil)
        case PostLogin(let username, let password):
            return ("/api/sessions", ["username": username, "password": password])
        case PostCreateUser(let username, let password):
            print(username, password)
            return ("/api/users", ["username": username, "password": password])
        case PostSendYak(let description, let image):
            sending = true
            return ("/api/yaks", ["description": description, "image": image])
        case GetMyYaks:
            sending = true
            return ("/api/my-yaks", nil)
        }
    }()

    let url = NSURL(string: Router.baseURL)
    let URLRequest = NSMutableURLRequest(URL: (url?.URLByAppendingPathComponent(result.path))!)
    let encoding = Alamofire.ParameterEncoding.JSON
    print(URLRequest)
    if sending == true {
        let defaults = NSUserDefaults.standardUserDefaults()
        if let token = defaults.objectForKey("auth_token") as? String {
            print(token)
            URLRequest.setValue(token, forHTTPHeaderField: "Authorization")
        }

    }
    URLRequest.addValue("application/json", forHTTPHeaderField: "Content-Type")
    let (encodedRequest, _) = encoding.encode(URLRequest, parameters: result.parameters)
    encodedRequest.HTTPMethod = method.rawValue
    return encodedRequest