feat: Enhance documentation and add .gitignore entries

- Add new documentation sections for PostgreSQL installer
  functions and usage examples.  Improves clarity and
  completeness of the documentation.
- Add new files and patterns to .gitignore to prevent
  unnecessary files from being committed to the repository.
  Improves repository cleanliness and reduces clutter.

docs/rhai/postgresclient_module_tests.md

@@ -9,9 +9,12 @@ The PostgreSQL client module provides the following features:
 1. **Basic PostgreSQL Operations**: Execute queries, fetch results, etc.
 2. **Connection Management**: Automatic connection handling and reconnection
 3. **Builder Pattern for Configuration**: Flexible configuration with authentication support
+4. **PostgreSQL Installer**: Install and configure PostgreSQL using nerdctl
+5. **Database Management**: Create databases and execute SQL scripts
 
 ## Prerequisites
 
+For basic PostgreSQL operations:
 - PostgreSQL server must be running and accessible
 - Environment variables should be set for connection details:
   - `POSTGRES_HOST`: PostgreSQL server host (default: localhost)
@@ -20,6 +23,11 @@ The PostgreSQL client module provides the following features:
   - `POSTGRES_PASSWORD`: PostgreSQL password
   - `POSTGRES_DB`: PostgreSQL database name (default: postgres)
 
+For PostgreSQL installer:
+- nerdctl must be installed and working
+- Docker images must be accessible
+- Sufficient permissions to create and manage containers
+
 ## Test Files
 
 ### 01_postgres_connection.rhai
@@ -34,6 +42,15 @@ Tests basic PostgreSQL connection and operations:
 - Dropping a table
 - Resetting the connection
 
+### 02_postgres_installer.rhai
+
+Tests PostgreSQL installer functionality:
+
+- Installing PostgreSQL using nerdctl
+- Creating a database
+- Executing SQL scripts
+- Checking if PostgreSQL is running
+
 ### run_all_tests.rhai
 
 Runs all PostgreSQL client module tests and provides a summary of the results.
@@ -66,6 +83,13 @@ herodo --path src/rhai_tests/postgresclient/01_postgres_connection.rhai
 - `pg_query(query)`: Execute a query and return the results as an array of maps
 - `pg_query_one(query)`: Execute a query and return a single row as a map
 
+### Installer Functions
+
+- `pg_install(container_name, version, port, username, password)`: Install PostgreSQL using nerdctl
+- `pg_create_database(container_name, db_name)`: Create a new database in PostgreSQL
+- `pg_execute_sql(container_name, db_name, sql)`: Execute a SQL script in PostgreSQL
+- `pg_is_running(container_name)`: Check if PostgreSQL is running
+
 ## Authentication Support
 
 The PostgreSQL client module will support authentication using the builder pattern in a future update.
@@ -85,7 +109,9 @@ When implemented, the builder pattern will support the following configuration o
 
 ## Example Usage
 
-```javascript
+### Basic PostgreSQL Operations
+
+```rust
 // Connect to PostgreSQL
 if (pg_connect()) {
     print("Connected to PostgreSQL!");
@@ -112,3 +138,51 @@ if (pg_connect()) {
     pg_execute(drop_query);
 }
 ```
+
+### PostgreSQL Installer
+
+```rust
+// Install PostgreSQL
+let container_name = "my-postgres";
+let postgres_version = "15";
+let postgres_port = 5432;
+let postgres_user = "myuser";
+let postgres_password = "mypassword";
+
+if (pg_install(container_name, postgres_version, postgres_port, postgres_user, postgres_password)) {
+    print("PostgreSQL installed successfully!");
+
+    // Create a database
+    let db_name = "mydb";
+    if (pg_create_database(container_name, db_name)) {
+        print(`Database '${db_name}' created successfully!`);
+
+        // Execute a SQL script
+        let create_table_sql = `
+            CREATE TABLE users (
+                id SERIAL PRIMARY KEY,
+                name TEXT NOT NULL,
+                email TEXT UNIQUE NOT NULL
+            );
+        `;
+
+        let result = pg_execute_sql(container_name, db_name, create_table_sql);
+        print("Table created successfully!");
+
+        // Insert data
+        let insert_sql = "#
+            INSERT INTO users (name, email) VALUES
+            ('John Doe', 'john@example.com'),
+            ('Jane Smith', 'jane@example.com');
+        #";
+
+        result = pg_execute_sql(container_name, db_name, insert_sql);
+        print("Data inserted successfully!");
+
+        // Query data
+        let query_sql = "SELECT * FROM users;";
+        result = pg_execute_sql(container_name, db_name, query_sql);
+        print(`Query result: ${result}`);
+    }
+}
+```