Added authorization URL to the Apis

src/main/java/org/scribe/builder/api/FoursquareApi.java

@@ -1,7 +1,11 @@
 package org.scribe.builder.api;
 
+import org.scribe.model.Token;
+
 public class FoursquareApi extends DefaultApi10a
 {
+  private static final String AUTHORIZATION_URL = "http://foursquare.com/oauth/authorize?oauth_token=%s";
+  
   @Override
   public String getAccessTokenEndpoint()
   {
@@ -13,4 +17,10 @@ public class FoursquareApi extends DefaultApi10a
   {
     return "http://foursquare.com/oauth/request_token";
   }
+  
+  @Override
+  public String getAuthorizationUrl(Token requestToken)
+  {
+    return String.format(AUTHORIZATION_URL, requestToken.getToken());
+  }
 }