allow starting from blank

ansible/migrate-to-docker.yaml

@@ -9,10 +9,27 @@
       become: true
       shell: cat /etc/dnsmasq.d/dhcp.conf || true
       register: dnsmasq_dhcp_result
+    - name: directory
+      become: true
+      file:
+        path: '{{ansible_user_dir}}/router'
+        state: directory
+        owner: '{{ ansible_user_id }}'
+        group: '{{ ansible_user_id }}'
     - name: read old docker-compose file
       become: '{{become_in_rsync}}'
       shell: 'cat {{ansible_user_dir}}/router/docker-compose.yml || true'
       register: docker_compose_result
+    - name: when docker-compose is available
+      set_fact:
+        docker_compose_header: '{{docker_compose_result.stdout}}'
+      when: docker_compose_result.stdout
+    - name: when docker-compose is not available
+      set_fact:
+        docker_compose_header: |
+          version: '2.4'
+          services:
+      when: not docker_compose_result.stdout
     - name: make a backup
       shell: 'cp -rf {{ansible_user_dir}}/router {{ansible_user_dir}}/router-backup'
     - name: dnsmasq.conf
@@ -42,7 +59,7 @@
       become: true
       copy:
         content: |
-          {{docker_compose_result.stdout}}
+          {{docker_compose_header}}
             dnsmasq:
               restart: always
               image: git-registry.mycard.moe/nanahira/dnsmasq:latest