Add rest-rate-limiting.md to translate into Russian

docs/guide-ru/rest-rate-limiting.md

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+Rate Limiting
+=============
+
+To prevent abuse, you should consider adding rate limiting to your APIs. For example, you may limit the API usage
+of each user to be at most 100 API calls within a period of 10 minutes. If too many requests are received from a user
+within the period of the time, a response with status code 429 (meaning Too Many Requests) should be returned.
+
+To enable rate limiting, the [[yii\web\User::identityClass|user identity class]] should implement [[yii\filters\RateLimitInterface]].
+This interface requires implementation of the following three methods:
+
+* `getRateLimit()`: returns the maximum number of allowed requests and the time period, e.g., `[100, 600]` means
+  at most 100 API calls within 600 seconds.
+* `loadAllowance()`: returns the number of remaining requests allowed and the corresponding UNIX timestamp
+  when the rate limit is checked last time.
+* `saveAllowance()`: saves the number of remaining requests allowed and the current UNIX timestamp.
+
+You may use two columns in the user table to record the allowance and timestamp information.
+And `loadAllowance()` and `saveAllowance()` can then be implementation by reading and saving the values
+of the two columns corresponding to the current authenticated user. To improve performance, you may also
+consider storing these information in cache or some NoSQL storage.
+
+Once the identity class implements the required interface, Yii will automatically use [[yii\filters\RateLimiter]]
+configured as an action filter for [[yii\rest\Controller]] to perform rate limiting check. The rate limiter
+will thrown a [[yii\web\TooManyRequestsHttpException]] if rate limit is exceeded. You may configure the rate limiter
+as follows in your REST controller classes,
+
+```php
+public function behaviors()
+{
+    $behaviors = parent::behaviors();
+    $behaviors['rateLimiter']['enableRateLimitHeaders'] = false;
+    return $behaviors;
+}
+```
+
+When rate limiting is enabled, by default every response will be sent with the following HTTP headers containing
+the current rate limiting information:
+
+* `X-Rate-Limit-Limit`: The maximum number of requests allowed with a time period;
+* `X-Rate-Limit-Remaining`: The number of remaining requests in the current time period;
+* `X-Rate-Limit-Reset`: The number of seconds to wait in order to get the maximum number of allowed requests.
+
+You may disable these headers by configuring [[yii\filters\RateLimiter::enableRateLimitHeaders]] to be false,
+like shown in the above code example.