Merge pull request #11 from VenusProtocol/docs/factories

[VEN-764][VEN-765][VEN-766][VEN-767] docs: add factories reference

Author: coreyar

isolated-lending/factories/README.md

@@ -0,0 +1,9 @@
+# Factories
+
+Factories are the contracts that deploy interest rate models and VToken proxies. [PoolRegistry](../pool-registry.md) uses these factories to create the necessary contracts when a new market is added to a pool.
+
+There are two contracts for interest rate models:
+* [WhitePaperInterestRateModelFactory](./white-paper-interest-rate-model-factory.md) deploys a linear interest rate model
+* [JumpRateModelFactory](./jump-rate-model-factory.md) deploys a piecewise linear interest rate model with a steep increase when the utilization is high
+
+[VTokenProxyFactory](./vtoken-proxy-factory.md) deploys an upgradeable proxy for the market itself. Contrary to the Core Pool, Isolated Pools uses a standard OpenZeppelin proxy for all contracts including VToken. All markets are upgradeable in Venus Isolated Pools.

isolated-lending/factories/jump-rate-model-factory.md

@@ -0,0 +1,32 @@
+# JumpRateModelFactory
+
+A factory for Jump Rate Model, an interest rate model with a steep increase after a certain utilization threshold called __kink__ is reached. This rate model uses the following formula for the borrow rate:
+
+* $borrow\_rate(u)=a_1 \cdot u + b$, when $u<kink$
+* $borrow\_rate(u)=a_1 \cdot kink + a_2  \cdot (u-kink) + b$, otherwise
+
+The parameters of this interest rate model can be adjusted by the owner.
+
+## deploy
+
+```solidity
+function deploy(
+    uint256 baseRatePerYear,
+    uint256 multiplierPerYear,
+    uint256 jumpMultiplierPerYear,
+    uint256 kink_,
+    address owner_
+) external returns (JumpRateModelV2)
+```
+
+Deploys a new Jump Rate Model.
+
+#### Parameters
+
+| Name | Type | Description |
+| ---- | ---- | ----------- |
+| `baseRatePerYear` | uint256 | $b$, the base interest rate which is the y-intercept when utilization rate is 0 |
+| `multiplierPerYear` | uint256 | $a_1$, the multiplier of utilization rate that gives the slope of the interest rate |
+| `jumpMultiplierPerYear` | uint256 | $a_2$, the multiplier of utilization rate after hitting a specified utilization point |
+| `kink_` | uint256 | $kink$, the utilization point at which the jump multiplier is applied |
+| `owner_` | address | the address that can adjust the interest rate model parameters |

isolated-lending/factories/vtoken-proxy-factory.md

@@ -0,0 +1,56 @@
+# VTokenProxyFactory
+
+This factory deploys a ERC-1967 compliant transparent proxy and initializes it with the implementation of VToken.
+
+## deploy
+
+```solidity
+function deployVTokenProxy(
+    VTokenArgs memory input
+) external returns (VToken)
+```
+
+#### Parameters
+
+| Name | Type | Description |
+| ---- | ---- | ----------- |
+| `input` | VTokenArgs memory | `VTokenArgs` struct with the parameters for the new market |
+
+The parameters are defined as follows:
+```
+struct VTokenArgs {
+    address underlying_;
+    ComptrollerInterface comptroller_;
+    InterestRateModel interestRateModel_;
+    uint256 initialExchangeRateMantissa_;
+    string name_;
+    string symbol_;
+    uint8 decimals_;
+    address payable admin_;
+    AccessControlManager accessControlManager_;
+    VTokenInterface.RiskManagementInit riskManagement;
+    address vTokenProxyAdmin_;
+    VToken tokenImplementation_;
+}
+
+struct RiskManagementInit {
+    address shortfall;
+    address payable riskFund;
+    address payable protocolShareReserve;
+}
+```
+
+| Name | Type | Description |
+| ---- | ---- | ----------- |
+| `underlying_` | address | The underlying BEP-20 token to list |
+| `comptroller_` | address | The pool Comptroller |
+| `interestRateModel_` | address | Interest rate model to use |
+| `initialExchangeRateMantissa_` | uint256 | The vToken to underlying exchange rate to start with |
+| `name_` | address | vToken name (usually it's "Venus " + underlying name) |
+| `symbol_` | address | vToken symbol (usually it's "v" + underlying symbol) |
+| `decimals_` | address | vToken decimals (the convention is to use 8 decimals for vTokens) |
+| `admin_` | address | vToken admin (should be Governance). Note that this is **not** the upgradeability administrator |
+| `accessControlManager_` | address | [AccessControlManager](../governance/access-control-manager.md) contract |
+| `riskManagement` | RiskManagementInit | Addreses of the [Shortfall](../shortfall.md), [Risk Fund](../risk-fund.md), and [Protocol Share Reserve](../protocol-share-reserve.md) contracts |
+| `vTokenProxyAdmin_` | address | The address of the upgradeability admin |
+| `tokenImplementation_` | address | voken implementation contract |

isolated-lending/factories/white-paper-interest-rate-model-factory.md

@@ -0,0 +1,25 @@
+# WhitePaperInterestRateModelFactory
+
+A factory for WhitePaperInterestRateModel, a simple model where the borrow rate depends linearly on the utilization:
+
+$borrow\_rate(u) = a \cdot u + b$
+
+The parameters of this interest rate model can not be updated after deployment. Pool risk managers need to deploy another interest rate model to change the curve.
+
+## deploy
+
+```solidity
+function deploy(
+    uint256 baseRatePerYear,
+    uint256 multiplierPerYear
+) external returns (WhitePaperInterestRateModel)
+```
+
+
+
+#### Parameters
+
+| Name | Type | Description |
+| ---- | ---- | ----------- |
+| `baseRatePerYear` | uint256 | $b$, the base interest rate which is the y-intercept when utilization rate is 0 |
+| `multiplierPerYear` | uint256 | $a_1$, the multiplier of utilization rate that gives the slope of the interest rate |