This pull request introduces the capability to specify a custom date column when using the range method. This enhancement provides greater flexibility in metric calculations, allowing users to filter and calculate metrics based on custom date fields.

Changes:

• Metric.php: Added a new method dateColumn(string $dateColumn) to allow the specification of a custom date column.
• Modified the getDateColumn method to return the custom date column if specified, defaulting to the model's created_at column otherwise.
• Updated existing methods to ensure compatibility with the new custom date column feature.

Tests:

• Added a new test CustomDateColumnTest.php to verify the functionality of using a custom date column for metric calculations.
  • This test checks the correct counting of users based on the email_verified_at column within a specified date range.
  • Ensured that the growth rate calculations are accurate when using the custom date column.

Impact:

• This feature maintains backward compatibility, as it defaults to using the model's created_at column if no custom date column is specified.
• Provides enhanced flexibility for users needing to perform metric calculations based on various date fields within their models.

Example Usage:

$data = Value::make(User::class)
    ->dateColumn('email_verified_at') // Specify custom date column
    ->range(15) // Define the date range
    ->count();