Update docs to add new methods

Author: bradymholt

README.md

@@ -56,6 +56,8 @@ The following methods are available in this library.
 | **Categories**             | [categories.get_categories(budget_id)](https://github.com/ynab/ynab-sdk-ruby/blob/master/docs/CategoriesApi.md#get_categories)                                                                                    | Returns all categories grouped by category group.     |
 |                            | [categories.get_category_by_id(budget_id, category_id)](https://github.com/ynab/ynab-sdk-ruby/blob/master/docs/CategoriesApi.md#get_category_by_id)                                                               | Returns a single category                             |
 |                            | [categories.get_month_category_by_id(budget_id, month, category_id)](https://github.com/ynab/ynab-sdk-ruby/blob/master/docs/MonthsApi.md#get_month_category_by_id)                                                    | Returns a single category for a specific budget month
+|                            | [categories.update_category(budget_id, category_id, data)](https://github.com/ynab/ynab-sdk-ruby/blob/master/docs/CategoriesApi.md#update_category)                                                    | Update an existing category
+|                            | [categories.update_month_category(budget_id, month, category_id, data)](https://github.com/ynab/ynab-sdk-ruby/blob/master/docs/CategoriesApi.md#update_month_category)                                                    | Update an existing month category
 | **Payees**                 | [payees.get_payees(budget_id)](https://github.com/ynab/ynab-sdk-ruby/blob/master/docs/PayeesApi.md#get_payees)                                                                                                    | Returns all payees                                    |
 |                            | [payees.get_payee_by_id(budget_id, payee_id)](https://github.com/ynab/ynab-sdk-ruby/blob/master/docs/PayeesApi.md#get_payee_by_id)                                                                                | Returns single payee                                  |
 | **Payee Locations**        | [payee_locations.get_payee_locations(budget_id)](https://github.com/ynab/ynab-sdk-ruby/blob/master/docs/PayeeLocationsApi.md#get_payee_locations)                                                                 | Returns all payee locations                           |
@@ -78,6 +80,8 @@ The following methods are available in this library.
 | **Scheduled Transactions** | [scheduled_transactions.get_scheduled_transactions(budget_id)](https://github.com/ynab/ynab-sdk-ruby/blob/master/docs/ScheduledTransactionsApi.md#get_scheduled_transactions)                                     | Returns all scheduled transactions                    |
 |                            | [scheduled_transactions.get_scheduled_transaction_by_id(budget_id, scheduled_transaction_id)](https://github.com/ynab/ynab-sdk-ruby/blob/master/docs/ScheduledTransactionsApi.md#get_scheduled_transaction_by_id) | Returns a single scheduled transaction                |
 |                            | [scheduled_transactions.create_scheduled_transaction(budget_id, data)](https://github.com/ynab/ynab-sdk-ruby/blob/master/docs/ScheduledTransactionsApi.md#create_scheduled_transaction)                           | Creates a single scheduled transaction                      |
+|                            | [scheduled_transactions.update_scheduled_transaction(budget_id, scheduled_transaction_id, data)](https://github.com/ynab/ynab-sdk-ruby/blob/master/docs/ScheduledTransactionsApi.md#update_scheduled_transaction)                           | Updates a single scheduled transaction                      |
+|                            | [scheduled_transactions.delete_scheduled_transaction(budget_id, scheduled_transaction_id)](https://github.com/ynab/ynab-sdk-ruby/blob/master/docs/ScheduledTransactionsApi.md#delete_scheduled_transaction)                           | Deletes a single scheduled transaction                      |
 
 ## Versioning