Add automatic build for docker images and publish to dockerhub with drone

.drone.yml

@@ -37,10 +37,21 @@ steps:
         settings:
             purge: true
             repo: varakh/filebin
+            username:
+                from_secret: dockerhub_user
+            password:
+                from_secret: dockerhub_key
             tags:
                 - latest
                 - 4.0.0
 
+    -   name: clean up
+        image: alpine
+        commands:
+            - apk update
+            - apk add bash
+            - bash -c "[[ -d $BUILD_DIR ]] && rm -rf $BUILD_DIR || echo 'Nothing to clean'"
+
     -   name: notify
         image: drillster/drone-email
         settings:
@@ -57,15 +68,8 @@ steps:
         when:
             status:
                 - failure
-
-    -   name: clean up
-        image: alpine
-        commands:
-            - apk update
-            - apk add bash
-            - bash -c "[[ -d $BUILD_DIR ]] && rm -rf $BUILD_DIR || echo 'Nothing to clean'"
 ---
 kind: signature
-hmac: 220cafe5d49c70697787b6cd29a4efbfb6b5d72162aefb3becf59285c3809bb7
+hmac: e2f9c0fce3829d85c03a504223fb6bb595a14061f9771b9c9f0e6a52548a6102
 
 ...