changelog and docs updates for 2.6

docs/additional-features/caching.md

@@ -0,0 +1,21 @@
+# Caching
+
+To improve performance, NetBox supports caching for most object and list views. Caching is implemented using Redis,
+and [django-cacheops](https://github.com/Suor/django-cacheops)
+
+Several management commands are avaliable for administrators to manaully invalidate cache entries in extenuating circumstances.
+
+To invalidate a specifc model instance (for example a Device with ID 34):
+```
+python netbox/manage.py invalidate dcim.Device.34
+```
+
+To invalidate all instance of a model:
+```
+python netbox/manage.py invalidate dcim.Device
+```
+
+To flush the entire cache database:
+```
+python netbox/manage.py invalidate all
+```