feat: add RETH pool README

Author: skellet0r

contracts/pools/reth/README.md

@@ -0,0 +1,20 @@
+# curve-contract/contracts/pools/reth
+
+[Curve rETH]()
+
+## Contracts
+
+-[`StableSwaprETH`](StableSwapRETH.vy): Curve stablecoin AMM contract
+
+## Deployments
+
+-[`CurveContractV3`](../../tokens/CurveTokenV3.vy):
+-[`LiquidityGaugeV2`](https://github.com/curvefi/curve-dao-contracts/blob/master/contracts/gauges/LiquidityGaugeV2.vy):
+-[`StableSwapRETH`](StableSwapRETH.vy):
+
+## Stablecoins
+
+Curve rETH pool supports swaps between ETH and [`rETH`](https://github.com/stafiprotocol/) staked ETH (rETH):
+
+-`ETH`: represented in the pool as `0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE`
+-`rETH`: [0x9559aaa82d9649c7a7b220e7c461d2e74c9a3593](https://etherscan.io/token/0x9559aaa82d9649c7a7b220e7c461d2e74c9a3593#code)