Merge pull request #56 from SamerZurub/addition_of_new_campaign_types

Addition of new backstage campaign types.

Author: vladimanaev

src/main/java/com/taboola/backstage/model/CampaignType.java

@@ -9,5 +9,7 @@
 public enum CampaignType {
     PAID,
     NATIVE,
-    EXCHANGE
+    EXCHANGE,
+    RTB_OPEN_EXCHANGE,
+    PMP
 }