Add Pod Priority to Glossary page (#12461)

* Add Pod Priority to Glossary page

* change id

content/en/docs/reference/glossary/pod-priority.md

@@ -0,0 +1,17 @@
+---
+title: Pod Priority
+id: pod-priority
+date: 2019-01-31
+full_link: https://kubernetes.io/docs/concepts/configuration/pod-priority-preemption/#pod-priority
+short_description: >
+  Pod Priority indicates the importance of a Pod relative to other Pods.
+
+aka:
+tags:
+- operation
+---
+ Pod Priority indicates the importance of a Pod relative to other Pods.
+
+<!--more-->
+
+[Pod Priority](https://kubernetes.io/docs/concepts/configuration/pod-priority-preemption/#pod-priority) gives the ability to set scheduling priority of a Pod to be higher and lower than other Pods — an important feature for production clusters workload.