[BIP-137] Enable bb-a-TUSD / bb-a-USD Gauge [Ethereum]

Summary:

This pool uses the composable stable pool factory and contains two boosted stable pool tokens bb-a-USD - Balancer’s AAVE boosted stable pool token, and bb-a-TUSD, True USD's AAVE boosted token. This is overall more efficient for TrueUSD who has deployed liquidity in the past with Balancer both on mainnet and polygon. Balancer protocol will be earning yield on both boosted portions of this pool, making the token pairing more efficient for both parties. This gauge would enter as a “core pool” under BIP-19, meaning protocol fees earned by this pool would be used to bribe for votes on it. The gauge can be uncapped based on the nature of the pool and market cap of TrueUSD.

References/Useful links:

USDC: Link to: • Website • Documentation • Github Page • Communities - Coingecko link True USD (TUSD) Link to: • Website • Documentation • Github Page • Communities - Discord link

Protocol Description:

bb-a-USD is a Balancer’s primary stable coin liquidity on mainnet, leveraging AAVE’s boosted strategy. bb-a-TUSD is the AAVE boosted form of TrueUSD, a centralized stable coin here on Balancer.

Motivation:

Balancer's heavy interest in taking over the yield bearing token space and increased capital efficiency through linear and boosted pool architecture continues to take effect. This provides better trading routes on the protocol and more sustainable pool options for liquidity providers to place their funds. There is more interest each week from different projects in regards to leveraging this tech and it is mutually beneficial to Balancer to permit for this healthy competition to emerge amongst gauges.

Specifications:

1. Governance: TUSD and USDC are centralized and does not have a governance forum.
2. Oracles: This pool only relies on the rate providers of the linear pools to inform when yield is earned.
3. Audits: See here
4. Centralization vectors: USDC and TUSD are inherently centralized.
5. Market History: See here.
6. Value: Balancer will earn the protocol fee on underlying bb-a-USD and bb-a-TUSD yield. BIP-19 will incentivize TVL to continue to grow here with trading volume and this implementation will continue to draw in new volume, as well as showcase the power of these pool types.

Link to pool: 0x53bc3cba3832ebecbfa002c12023f8ab1aa3a3a0 Link to gauge: 0x7d5cAd03DD554ECaDF273935Ea10bfa964fB7d84