chore(mariadb): add role-README, update collection README

README.md

@@ -7,6 +7,7 @@ and configuring basic system utilities like gnupg, ssh etc
 
 - [`git`](roles/git/README.md): configures git on the target system
 - [`gnupg`](roles/gnupg/README.md): configures gnupg on the target system
+- [`mariadb`](roles/mariadb/README.md): runs [MariaDB Server](https://mariadb.org/), one of the world's most popular open source relational database
 - [`nginx`](roles/nginx/README.md): [nginx](https://www.nginx.com/),
   an advanced load balancer, webserver and reverse proxy.
 

roles/mariadb/README.md

@@ -0,0 +1,19 @@
+# `finallycoffee.base.mariadb` ansible role
+
+This role deploys a MariaDB instance in a docker container.
+
+## Usage
+
+The role expects the following variables to be populated with values and/or secrets:
+
+```yaml
+mariadb_root_password: #mariadb root password
+mariadb_database: # name of the database to create
+mariadb_username: # name of a user to auto-create and assign permission on the mariadb_database
+mariadb_password: # password of the user in mariadb_username
+```
+
+## Requirements
+
+- Docker installed
+- python-docker present on target system for ansible to be able to talk with the docker API.