anchor.diff:  
   ## Group Transactions
   
  -Resources related to transactions in the API.
  +These calls deal with moving credit around in the system. 
   
  
positive.code: FORMAT: 1A
  HOST: http://notecase.apiblueprint.org/
  
  # Notecase
  
  
negative.code: Once the accounts are set up, three kinds of trasnactions are possible:
  
  1. **Recharge**: This recharges a wallet by withdrawing credit from a recharger - typically when a payment processor confirms a user's payment towards their wallet balance, or a loyalty award is given to the user.
  2. **Spend**: The user spends the credit in their wallet, towards a product or service revenue account. This is a typical user purchase.
  3. **Refund**: A revenue account either parially or fully returns a user's *spend*, typically because the purchse could not be completed or the product was faulty.
  
  # Double Entry Accounting
  Notecase follows the double entry accounting protocol. This is how the API concepts relate to normal acounting practices:
  
  * *Rechargers* are **Asset** accounts, and thus tend to have an internal negative balance.
  * *Wallets* are **Liability** accounts, where the credit is owed to the users.
  * *Revenues* are **Owner's Equity** accounts, because these are revnues that the owner of the system has earned.
  * Going by the standard equation, **Assets = Liabilities + Owner's Equity**. This equation should always hold true, and is used internally and externally to balance the books.
  * A *Recharge* transaction will move credit from a  Recharger (Asset) to a Wallet (Liability).
  * A *Spend* transaction will move credit from a  Wallet (Liability) to a revenue account (Owner's Equity).
  * A *Refund* transaction will move credit from a  Revenue account (Owner's Equity) to a Wallet (Liability).
  ## Group Account Management
  
  These calls relate to account management, including creating accounts and checking balances.
  
  ## Wallet [/wallets/{id}]
  
  Wallets are user accounts that hold their credit.
  
  ## Create a wallet account [POST]
  
  This call is idempotent w.r.t the `ref` supplied. The JSON `data` is opaque and used only for the client's reference.
  
  + `ref` (string) - The external ID of the user wallet
  + `data` (object) - An arbitrary JSON data associated with this wallet
  
  + Request (application/json)
  
  