Include volume mounts in pre-deploy

plays/lib/volumes.yml

@@ -0,0 +1,6 @@
+---
+- name: Attach volume mounts
+  dokku_storage:
+    app: "{{ app }}"
+    mounts: "{{ item }}"
+  with_items: "{{ lookup('vars', 'mounts', default=[]) }}"

plays/pre_deploy.yml

@@ -22,5 +22,8 @@
       with_items: "{{ db }}"
       when: db is defined
 
+    - name: Include volume tasks
+      include: ./lib/volumes.yml
+
     - name: Include env tasks
       include: ./lib/env.yml