added support for Debian based os

tasks/main.yml

@@ -1,9 +1,17 @@
 ---
 - name: Enable nginx repo.
   copy: src=nginx.repo dest=/etc/yum.repos.d/nginx.repo owner=root group=root mode=644
+  when: ansible_os_family == 'RedHat'
 
 - name: Ensure nginx is installed.
   yum: pkg=nginx state=installed enablerepo=nginx
+  when: ansible_os_family == 'RedHat'
+
+- name: Ensure nginx is installed.
+  apt: pkg=nginx state=installed update_cache=true
+  notify:
+    - restart nginx
+  when: ansible_os_family == 'Debian'
 
 - name: Copy nginx configuration in place.
   template: >