Add revision to Entity interface

src/main/java/de/thm/arsnova/entities/DbUser.java

@@ -45,12 +45,12 @@ public class DbUser implements Entity {
 	}
 
 	@JsonView(View.Persistence.class)
-	public String getRev() {
+	public String getRevision() {
 		return rev;
 	}
 
 	@JsonView(View.Persistence.class)
-	public void setRev(String rev) {
+	public void setRevision(String rev) {
 		this.rev = rev;
 	}
 

src/main/java/de/thm/arsnova/entities/Entity.java

@@ -24,6 +24,9 @@ public interface Entity {
 	String getId();
 	void setId(String id);
 
+	String getRevision();
+	void setRevision(String id);
+
 	@JsonView(View.Persistence.class)
 	default Class<? extends Entity> getType() {
 		return getClass();