Update README.md

README.md

@@ -31,7 +31,8 @@ The example of one sample is provided below
 ### Data Fields
 
 - `app_id`: application ID.
-- `transactions`: an array of transactions where each transaction is represented as a 20-dimensional array, each element of the array represents a corresponding feature from the following list.
+- `history`: an array of transactions where each transaction is represented as a 20-dimensional array, each element of the array represents a corresponding feature from the following list.
+  - `app_id`: application ID.
   - `amnt`: normalized transaction amount. 0.0 - corresponds to omissions.
   - `currency`: transaction currency ID.
   - `operation_kind`: ID of the transaction type.