adjusted guide of date validator

docs/guide/tutorial-core-validators.md

@@ -102,18 +102,27 @@ is as specified by the `operator` property.
 ```
 
 This validator checks if the input value is a date, time or datetime in a proper format.
-Optionally, it can convert the input value into a UNIX timestamp and store it in an attribute
+Optionally, it can convert the input value into a UNIX timestamp or other machine readable format and store it in an attribute
 specified via [[yii\validators\DateValidator::timestampAttribute|timestampAttribute]].
 
 - `format`: the date/time format that the value being validated should be in. 
    This can be a date time pattern as described in the [ICU manual](http://userguide.icu-project.org/formatparse/datetime#TOC-Date-Time-Format-Syntax).
    Alternatively this can be a string prefixed with `php:` representing a format that can be recognized by the PHP 
    `Datetime` class. Please refer to <http://php.net/manual/en/datetime.createfromformat.php> on supported formats.
    If this is not set, it will take the value of `Yii::$app->formatter->dateFormat`.
+   See the [[yii\validators\DateValidator::$format|API documentation]] for more details.
+
 - `timestampAttribute`: the name of the attribute to which this validator may assign the UNIX timestamp
   converted from the input date/time. This can be the same attribute as the one being validated. If this is the case,
   the original value will be overwritten with the timestamp value after validation.
   See ["Handling date input with the DatePicker"](widget-jui#datepicker-date-input) for a usage example.
+
+  Since version 2.0.4, a format and timezone can be specified for this attribute using
+  [[yii\validators\DateValidator::$timestampAttributeFormat|$timestampAttributeFormat]] and
+  [[yii\validators\DateValidator::$timestampAttributeTimeZone|$timestampAttributeTimeZone]].
+
+- Since version 2.0.4 it is also possible to specify a [[yii\validators\DateValidator::$min|minimum]] or
+  [[yii\validators\DateValidator::$max|maximum]] timestamp.
 
 In case the input is optional you may also want to add a [default value filter](#default) in addition to the date validator
 to ensure empty input is stored as `NULL`. Other wise you may end up with dates like `0000-00-00` in your database