Added session timestamp in backend

src/main/java/de/thm/arsnova/controller/SessionController.java

@@ -101,7 +101,8 @@ public class SessionController extends AbstractController {
 				session.setName(session.getName() + appendix);
 				session.setShortName(session.getShortName() + appendix);
 			}
-		}
+		}		
+		
 		final Session newSession = sessionService.saveSession(session);
 
 		if (newSession == null) {

src/main/java/de/thm/arsnova/dao/CouchDBDao.java

@@ -326,6 +326,7 @@ public class CouchDBDao implements IDatabaseDao {
 		sessionDocument.put("active", true);
 		sessionDocument.put("courseType", session.getCourseType());
 		sessionDocument.put("courseId", session.getCourseId());
+		sessionDocument.put("creationTime", session.getCreationTime());
 		try {
 			database.saveDocument(sessionDocument);
 		} catch (final IOException e) {

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

@@ -37,6 +37,7 @@ public class Session implements Serializable {
 	private String courseType;
 	private String courseId;
 	private List<String> _conflicts;
+	private long creationTime;
 
 	private String _id;
 	private String _rev;
@@ -145,6 +146,14 @@ public class Session implements Serializable {
 	public boolean isCourseSession() {
 		return getCourseId() != null && !getCourseId().isEmpty();
 	}
+	
+	public long getCreationTime() {
+		return creationTime;
+	}
+
+	public void setCreationTime(long creationTime) {
+		this.creationTime = creationTime;
+	}
 
 	@Override
 	public String toString() {