Approval in backend

backend/cs/object_relation.json

@@ -33,6 +33,7 @@
         "select_a_museum": "Vyberte muzeum",
         "links_object_with": "Propoj\u00ed objekt s",
         "tag_or_relation": "Kl\u00ed\u010dov\u00e9 slovo nebo vztah",
-        "add_exhibition": "Connect to a exhibition"
+        "add_exhibition": "Connect to a exhibition",
+        "add_series": "Connect to a series"
     }
 }