Add drone.io support

.drone.yml

@@ -0,0 +1,11 @@
+build:
+  backend:
+    image: morrisjobke/nextcloud-ci-php7:1.0
+    commands:
+      - git submodule update --init
+      - ./occ maintenance:install --database-name oc_autotest --database-user oc_autotest --admin-user admin --admin-pass admin --database sqlite --database-pass=''
+      - ./autotest.sh sqlite
+
+compose:
+  cache:
+    image: redis