dev comment logic for check max users

src/main/java/ru/soune/nocopy/entity/referral/Referral.java

@@ -25,6 +25,9 @@ public class Referral {
     @Column(name = "total_income")
     private int totalIncome = 0;
 
+    @Column(name = "available_income")
+    private int availableIncome = 0;
+
     @Column(name = "is_active")
     private boolean isActive = false;