Correction of groups endpoint

buisnesslogic/src/main/java/com/plannaplan/entities/Groups.java

@@ -30,6 +30,10 @@ public class Groups {
     public Groups() {
     }
 
+    public Long getId() {
+        return this.id;
+    }
+
     public Lecturer getLecturer() {
         return lecturer;
     }

buisnesslogic/src/main/java/com/plannaplan/entities/Lecturer.java

@@ -47,4 +47,9 @@ public class Lecturer {
     public Lecturer() {
     }
 
+    @Override
+    public String toString() {
+        return String.format("%s %s %s", this.title, this.name, this.surname);
+    }
+
 }