docs(incentive-manager): add readme to incentive manager

contracts/liquidity_hub/incentive-manager/README.md

@@ -1,4 +1,93 @@
 # Incentive Manager
 
-The Incentive Manager is the V2 iteration of the original incentives. This is a monolithic contract that handles all
+The Incentive Manager is the V2 iteration of the original incentives system; this is a monolithic contract that handles all
 the incentives-related logic.
+
+## How it works
+
+The Incentives system is now completely encapsulated within one contract called the Incentive Manager. The Incentive 
+Manager has two main concepts; an `Incentive`, defined as a reward to be distributed and a `Position`, defined as a 
+user's liquidity in a pool locked in the contract.
+
+Users of the Liquidity Hub, when providing liquidity, can opt to lock their LP shares which will in turn send them to 
+the Incentive Manager until they are unlocked.
+
+### Incentives
+
+Creating incentives is permissionless, and incentives can be perpetual. This means they can be expanded forever. Anyone
+can create an incentive by calling the `ManageIncentive` message with the `IncentiveAction::Fill` action and paying the 
+incentive creation fee, which is sent to the Bonding Manager. 
+
+Users can decide to provide an identifier, which they can later use to top up or close the incentive. If no identifier is
+provided, the contract will generate one.
+
+#### Topping up an Incentive
+
+To top up an incentive, the owner of the incentive must call `ManageIncentive` with the `IncentiveAction::Fill` action. 
+The user must provide the same identifier as the original incentive. The incentive can only be topped up with the same 
+token as the original incentive, and the amount must be a multiple of the original incentive's amount.
+
+#### Closing an Incentive
+
+To close an incentive, the owner of the incentive or the owner of the contract must call `ManageIncentive` with the 
+`IncentiveAction::Close` action with the identifier of the incentive to be closed. The incentive will be closed, and the
+remaining tokens will be sent to the owner of the incentive.
+
+#### Reward Distribution
+
+Incentive rewards are distributed every epoch, which is created by the Epoch Manager. Whenever an epoch is created; the 
+Incentive Manager gets called via the `EpochChangedHook` hook, alerting the contract that a new epoch has been created. 
+The contract will then take snapshots for every LP token in the contract and save it in the `LP_WEIGHT_HISTORY` map for 
+the current epoch. That helps to calculate the rewards when users claim them.
+
+The maximum number of concurrent incentives for a given LP denom is defined when the contract is instantiated, and it is
+stored in the config as `max_concurrent_incentives`.
+
+
+### Positions
+
+Positions can be created, expanded (topped up), or withdrawn. This is done via the `ManagePosition` 
+message, followed by the desired action, i.e. `PositionAction::Fill`, `PositionAction::Close` or `PositionAction::Withdraw`.
+When a user creates a position, it must provide an unlocking duration. The unlocking duration is the time it takes in 
+seconds to unlock the position, which is necessary to withdraw the LP tokens from the contract.
+
+#### Topping up a Position
+
+When a user creates a position, the LP tokens are locked in the contract. The user can't withdraw them until the unlocking 
+duration is complete. To expand a position, the user must call `ManagePosition` with the `PositionAction::Fill` action 
+using the same position identifier as the original position. In this case, since it's considered to be the same position,
+any changes in the unlocking duration parameter passed along with the `PositionAction::Fill` action will be ignored. 
+Instead, the one in the original position will be used.
+
+If a user doesn't provide an identifier when creating a position, the contract will generate one.
+
+The minimum unlocking duration is 1 day, and the maximum is 365 days.
+
+#### Closing a Position
+
+Closing a position is done by calling `ManagePosition` with the `PositionAction::Close` action. The user must provide the 
+identifier of the position to be closed. Once this action is triggered, the `Position.open` state is set to false, and 
+`expiring_at` is set to the block height after which the position will be able to be withdrawn.
+
+#### Withdrawing a Position
+
+Once the unlocking duration is complete, the user can withdraw the LP tokens from the contract by calling the `ManagePosition` 
+with the `PositionAction::Withdraw` action. Alternatively, if the user doesn't want to wait for the unlocking duration to 
+complete, it is possible to do an emergency withdrawal by passing `true` on the `emergency_unlock` parameter. This will 
+unlock and withdraw the position immediately, but the user will pay a penalty fee that will go the Bonding Manager and 
+distributed to the bonders.
+
+Once the user closes and withdraws the position, they receive their LP tokens back.
+
+### Claiming Incentive Rewards
+
+Users can claim incentive rewards from active incentives for their LP tokens, only if they have a position in the 
+contract. Users can only claim rewards for future epochs, i.e. after the epoch in which the position was created. 
+
+Incentive rewards are distributed based on the user's share of the total LP tokens in the contract. So if there's a total 
+of 100 LP tokens in the contract, and a user has 10 LP tokens, the user will receive 10% of the rewards for that epoch, 
+for that given incentive.
+
+To claim rewards, the user must call the `Claim` message. Once that's done, the contract will save the epoch in which the 
+claim was made in `LAST_CLAIMED_EPOCH`, and will sync the user's LP weight history saved in `LP_WEIGHT_HISTORY`. This helps 
+computing the rewards for the user.