Module ledger

A Ledger implementation for stakers.

A StakingLedger encapsulates all the state and logic related to the stake of bonded stakers, namely, it handles the following storage items:

• Bonded: mutates and reads the state of the controller <> stash bond map (to be deprecated soon);
• Ledger: mutates and reads the state of all the stakers. The Ledger storage item stores instances of StakingLedger keyed by the staker’s controller account and should be mutated and read through the StakingLedger API;
• Payee: mutates and reads the reward destination preferences for a bonded stash.
• Staking locks: mutates the locks for staking.

NOTE: All the storage operations related to the staking ledger (both reads and writes) MUST be performed through the methods exposed by the StakingLedger implementation in order to ensure state consistency.