add mailgun

Author: alrocar

tinybird/datasources/mailgun.datasource

@@ -21,5 +21,5 @@ SCHEMA >
     `user_variables` JSON `json:$.record.event-data.user-variables` DEFAULT '{}'
 
 ENGINE "MergeTree"
-ENGINE_PARTITION_KEY "toYYYYMM(timestamp)"
-ENGINE_SORTING_KEY "event, timestamp"
+ENGINE_PARTITION_KEY "toYYYYMM(date)"
+ENGINE_SORTING_KEY "event, date"