restore the transifex configuration

This reverts commit 6957aaa.

Author: xordoquy

.tx/config

@@ -0,0 +1,9 @@
+[main]
+host = https://www.transifex.com
+lang_map = sr@latin:sr_Latn, zh-Hans:zh_Hans, zh-Hant:zh_Hant
+
+[django-rest-framework.djangopo]
+file_filter = rest_framework/locale/<lang>/LC_MESSAGES/django.po
+source_file = rest_framework/locale/en_US/LC_MESSAGES/django.po
+source_lang = en_US
+type = PO