Add parse-log doc

support/doc/tools.md

@@ -85,6 +85,16 @@ $ node dist/server/tools/upload.js --help
 
 These scripts should be run on the server, in `peertube-latest` directory.
 
+### parse-log
+
+To parse PeerTube last log file:
+
+```
+$ sudo -u peertube NODE_CONFIG_DIR=/var/www/peertube/config NODE_ENV=production npm run parse-log -- --level info
+```
+
+`--level` is optional and could be `info`/`warn`/`error`
+
 ### create-transcoding-job.js
 
 You can use this script to force transcoding of an existing video.