add .drone.yml

.drone.yml

@@ -0,0 +1,26 @@
+kind: pipeline
+name: default
+
+steps:
+  - name: restore-cache
+    image: drillster/drone-volume-cache
+    restore: true
+    mount:
+      - ./node_modules
+    volumes:
+      - /tmp/cache:/cache
+  - name: install
+    image: node
+    commands:
+      - yarn install --frozen-lockfile
+  - name: restore-cache
+    image: drillster/drone-volume-cache
+    rebuild: true
+    mount:
+      - ./node_modules
+    volumes:
+      - /tmp/cache:/cache
+  - name: build
+    image: node
+    commands:
+      - yarn build --prefix-paths