Stable e-commerce Currency for DeepOnion

A Cryptocurrency needs to be stable to be viable for Online shopping and attractive to buyers, sellers of goods and services. Deeponion Developers could create a stable cryptocurrency to support or supplement Onion.
I don't know much about the Technical aspects of cryptocurrency volatility but I have some basic idea of what needs to be done to keep things stable.

I propose the creation of a Deeonion second currency (or cryptocurrency) for Purchasing and selling of goods and services. The second currency would be as stable as fiat currencies while the main cryptocurrency (Onion) is used just for Speculation.
Let's call the stabe Currency Stonion (Stable Onion) or Onion.S (S for Stable).

Stonion cryptocurrency may be incorporated into the existing Onion Blockchain to move in & out of Onion's overall reserve and help keep Onion price up & valuable.

Stonion stability can be achieved by depositing X amount of main fiat ($, € or ¥) currency on a transparent online Bank. The X amount of fiat currency must be greater or equal to total amount of Stonions available. The price of 1 Stonion would be equal to 1 US dollar, 1 Yen or 1 Euro for example. Whenever the total Stonion supply goes up, it must reflect on the fiat in the transparent Bank. Example: if the total available Stonions increase to 100, 000 Stonions (1 Stonion = $1), its fiat equivalent must increase to $100, 000 as well. The fiat in the Transparent bank acts as safety and stability guarantee for users of Stonion currency .

When a holder sells his/her Stonions for fiat, the Stonions are automatically destroyed and its equivalent in fiat is subtracted from the fiat in the transparent online bank . This is to help maintain the stability of Stonion currency.
When a buyer wants to convert his fiat to Stonion, Stonion is generated for him/her and his/her fiat is deposited in the transparent online bank.

Deeponion Developers could kickstart this project with 50000 stonions with its fiat equivalent ($50000)deposited in a transparent online bank Or they could just let it develop naturally by letting buyers purchase their first Stonions and the fiat equivalent deposited in a transparent on Bank.