add eventDTO

src/main/java/mops/gruppen2/domain/EventDTO.java

@@ -0,0 +1,13 @@
+package mops.gruppen2.domain;
+
+import lombok.Value;
+import org.springframework.data.relational.core.mapping.Table;
+
+@Value
+@Table("event")
+public class EventDTO {
+    long event_id;
+    long group_id;
+    String user_id;
+    String event_payload;
+}