update docs

docs/drivers/mysql.md

@@ -1,3 +1,42 @@
 # MySQL Driver
 
-In progress...
+MySQL driver is a driver for MySQL database. It uses PDO to connect to the database and execute queries.
+
+# Usage
+
+To use MySQL driver you need to create a new instance of `MySQLDriver` and pass it into `QueryRunner`:
+
+```php
+use ArekX\PQL\Drivers\Pdo\MySql\MySqlDriver;
+use ArekX\PQL\Drivers\Pdo\MySql\MySqlQueryBuilder;
+use ArekX\PQL\QueryRunner;
+
+
+$driver = MySqlDriver::create([
+    'dsn' => 'mysql:host=127.0.0.1;dbname=your_database',
+    'username' => 'username',
+    'password' => 'password',
+]);
+
+$builder = new MySqlQueryBuilder();
+
+// Create a runner for your driver and builder, this should be done once in your application
+$runner = QueryRunner::create($driver, $builder);
+```
+
+Driver handles the PDO connection to the database and executes the compiled queries.
+Builder is used to compile the queries into a format that the driver can understand.
+Runner is used to execute the queries and fetch the results.
+
+# Running a query
+
+To run a query you need to create a query object and pass it into the runner.
+Lets do a simple select query to get all users from the database:
+
+```php
+use function \ArekX\PQL\Sql\{select, all};
+
+$query = select('*')->from('user')->where(all(['is_active' => 1]));
+
+$results = $runner->fetchAll($query); // Results are returned here.
+```

docs/index.md

@@ -20,13 +20,6 @@ Following systems are supported:
 
 * [MySQL](drivers/mysql.md) - MySQL database via PDO
 
-### Custom drivers
-
-Drivers which are implemented are not limited to Relational Database Systems meaning other drivers
-can be easily implemented for non-database or no-sql database systems like Redis, ElasticSearch, MongoDB, etc.
-
-For implementing a custom driver see [here](custom-drivers.md).
-
 ## Testing
 
 After installing the dependencies run `composer test`