fixed attachments storage doc

doc/CONFIGURATION.md

@@ -82,7 +82,7 @@ storage config above like this:
 * `session_store`: `active_record_store`, `cache_store`, or `cookie_store` (default: cache_store)
 * [`omniauth_direct_login_provider`](#omniauth-direct-login-provider) (default: nil)
 * [`disable_password_login`](#disable-password-login) (default: false)
-* [`attachments_store`](#attachments-store) (default: file)
+* [`attachments_storage`](#attachments-storage) (default: file)
 
 ### disable password login
 
@@ -109,14 +109,14 @@ If this option is active /login will lead directly to the configured omniauth pr
 Note that this does not stop a user from manually navigating to any other
 omniauth provider if additional ones are configured.
 
-### attachments store
+### attachments storage
 
 *default: file*
 
 Attachments can be stored using fog as well. You will have to add further configuration through `fog`, e.g. for Amazon S3:
 
 ```
-attachments_store: fog
+attachments_storage: fog
 fog:
   directory: bucket-name
   credentials: