Added role for installing mysql

mysql/tasks/main.yml

+---
+# file: roles/mysql/tasks/main.yml
+
+- name: ensure mysql packages are installed
+  apt: name={{ item }} state=latest
+  with_items:
+    - mysql-server
+    - python-mysqldb
+  tags:
+    - packages
+    - mysql
+
+- name: ensure mysql is started
+  service: name=mysql state=running enabled=yes
+  tags:
+    - service
+    - mysql