added arm build

.drone.yml

@@ -1,5 +1,9 @@
 kind: pipeline
-name: default
+name: docker-amd
+
+platform:
+  os: linux
+  arch: amd64
 
 steps:
   - name: docker
@@ -9,4 +13,22 @@ steps:
       username:
         from_secret: USERNAME
       password:
-        from_secret: PASSWORD
+        from_secret: PASSWORD
+
+---
+kind: pipeline
+name: docker-arm
+
+platform:
+  os: linux
+  arch: arm
+
+steps:
+  - name: docker
+    image: plugins/docker
+    settings:
+      repo: samuelph/feed2toot
+      username:
+        from_secret: USERNAME
+      password:
+        from_secret: PASSWORD