added getting bookmarks from the database

app/src/main/java/com/example/taskboxx/Dashboard.java

@@ -73,6 +73,7 @@ public class Dashboard extends AppCompatActivity
         if (drawer.isDrawerOpen(GravityCompat.START)) {
             drawer.closeDrawer(GravityCompat.START);
         } else {
+            mAuth.getInstance().signOut();
             super.onBackPressed();
         }
     }