While repleneshing trading balance, the user’s trading account
additionally receives % from the amount of which he replenished
and from which there was a promo code, but no more than 1 BTC.
For example, 35% promo code on refill. User deposited 2 btc. He will receive
0,35 over it.
User deposits 0,5 btc for 50% promo code. He will recieve 0,25 over it.