supports local file system object storage and use it as the default avatar provider

conf/ezbookkeeping.ini

@@ -92,6 +92,13 @@ level = info
 # For "file" mode only, log file path (relative or absolute path)
 log_path = log/ezbookkeeping.log
 
+[storage]
+# Object storage type, supports "local_filesystem" currently
+storage_type = local_filesystem
+
+# For "local_filesystem" storage only, the storage root path (relative or absolute path)
+local_filesystem_path = storage/
+
 [uuid]
 # Uuid generator type, supports "internal" currently
 generator_type = internal
@@ -153,9 +160,10 @@ enable_forget_password = true
 forget_password_require_email_verify = false
 
 # User avatar provider, supports the following types:
+# "internal": Use the internal object storage to store user avatar (refer to "storage" settings), supports updating avatar by user self
 # "gravatar": https://gravatar.com
 # Leave blank if you want to disable user avatar
-avatar_provider =
+avatar_provider = internal
 
 [data]
 # Set to true to allow users to export their data