add fedora mirror documentation

docs/resources/resources.md

@@ -55,3 +55,17 @@
 * Linuxsoft [/mnt/data1](https://filer-carbon.cern.ch/grafana/d/000000111/cephfs-detail?orgId=1&refresh=1m&fullscreen&panelId=15&from=now-90d&to=now&var-cluster=flax&var-share=303fadd2-188b-4d27-984b-cc91bdfbbb73)
 * Linuxsoft [/mnt/data2](https://filer-carbon.cern.ch/grafana/d/000000111/cephfs-detail?orgId=1&refresh=1m&fullscreen&panelId=15&from=now-90d&to=now&var-cluster=flax&var-share=0d0757df-6220-4a27-81e7-51a38cd7ecdc)
 * Koji [/koji](https://filer-carbon.cern.ch/grafana/d/000000111/cephfs-detail?orgId=1&refresh=1m&var-cluster=flax&var-share=f51e1a94-b1ff-4f2c-9686-c7e9835e0f6c&fullscreen&panelId=15&from=now-90d&to=now)
+
+## External resources
+
+* Fedora mirror:
+    * Fedora uses the self service [mirror manager](https://admin.fedoraproject.org/mirrormanager/) where mirror admins can update their sites/hosts/distributions. The upstream documentation on this page can be found [here](https://fedoraproject.org/wiki/Infrastructure/Mirroring#MirrorManager:_the_Fedora_Mirror_Management_system)
+    * A Fedora account is required to access the mirror manager. We have a generic 'cern' account and the credentials can be seen through:
+```
+$ tbag show --hg lxsoft fedora_username
+$ tbag show --hg lxsoft fedora_password
+```
+If required, though should not be:
+```
+$ tbag show --hg lxsoft fedora_security_question_answer
+```