add serialization template to UDQAssign

opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQAssign.hpp

@@ -47,6 +47,13 @@ public:
             return selector == data.selector &&
                    value == data.value;
         }
+
+        template<class Serializer>
+        void serializeOp(Serializer& serializer)
+        {
+            serializer(selector);
+            serializer(value);
+        }
     };
 
     UDQAssign();
@@ -64,6 +71,14 @@ public:
 
     bool operator==(const UDQAssign& data) const;
 
+    template<class Serializer>
+    void serializeOp(Serializer& serializer)
+    {
+        serializer(m_keyword);
+        serializer(m_var_type);
+        serializer.vector(records);
+    }
+
 private:
     std::string m_keyword;
     UDQVarType m_var_type;