fix: add k8s deployments example (casdoor#446)

Author: ComradeProgrammer

k8s.yaml

@@ -0,0 +1,56 @@
+# this is only an EXAMPLE of deploying casddor in kubernetes
+# please modify this file according to your requirements
+apiVersion: v1
+kind: Service
+metadata:
+  #EDIT IT: if you don't want to run casdoor in default namespace, please modify this field
+  #namespace: casdoor
+  name: casdoor-svc
+  labels:
+    app: casdoor
+spec:
+  #EDIT IT: if you don't want to run casdoor in default namespace, please modify this filed
+  type: NodePort
+  ports:
+    - port: 8000
+  selector:
+    app: casdoor
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  #EDIT IT: if you don't want to run casdoor in default namespace, please modify this field
+  #namespace: casdoor
+  name: casdoor-deployment
+  labels:
+    app: casdoor
+spec:
+  #EDIT IT: if you don't use redis, casdoor should not have multiple replicas
+  replicas: 1
+  selector:
+    matchLabels:
+      app: casdoor
+  template:
+    metadata:
+      labels:
+        app: casdoor
+    spec:
+      containers:
+        - name: casdoor-container
+          image: casbin/casdoor:latest
+          imagePullPolicy: Always
+          ports:
+            - containerPort: 8000
+          volumeMounts:
+            # the mounted directory path in THE CONTAINER
+            - mountPath: /conf
+              name: conf
+          env:       
+            - name: RUNNING_IN_DOCKER
+              value: "true"
+      #if you want to deploy this in real prod env, consider the config map
+      volumes:
+        - name: conf
+          hostPath:
+            #EDIT IT: the mounted directory path in THE HOST
+            path: /conf