Update the readme to note that AWS requires the message group id and deduplicator ids must be strings and will pass through the strval() method.

Author: patrickcarlohickman

README.md

@@ -139,6 +139,8 @@ Currently, by default, all queued jobs will be lumped into one group, as defined
 
 The group id must not be empty, must not be more than 128 characters, and can contain alphanumeric characters and punctuation (``!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~``).
 
+Additionally, AWS enforces that the group id must be a string type. While typehinted in docblocks, variable types are not enforced in this package. To prevent AWS errors, the assigned message group will be converted to a string using the `strval()` method before being sent to AWS.
+
 In a future release, the message group will be able to be assigned to a function, like the deduplicator below.
 
 #### Deduplication
@@ -273,7 +275,7 @@ The deduplicators work by generating a deduplication id that is sent to the queu
 
 If you have some custom logic that needs to be used to generate the deduplication id, you can register your own custom deduplicator. The deduplicators are stored in the IoC container with the prefix `queue.sqs-fifo.deduplicator`. So, for example, the `unique` deduplicator is aliased to `queue.sqs-fifo.deduplicator.unique`.
 
-Custom deduplicators are created by registering a new prefixed alias in the IoC. This alias should resolve to a new object instance that implements the `ShiftOneLabs\LaravelSqsFifoQueue\Contracts\Queue\Deduplicator` contract. You can either define a new class that implements this contract, or you can create a new `ShiftOneLabs\LaravelSqsFifoQueue\Queue\Deduplicators\Callback` instance, which takes a `Closure` that performs the deduplication logic. The defined `Closure` should take two parameters: `$payload` and `$queue`, where `$payload` is the `json_encoded()` message to send to the queue, and `$queue` is the name of the queue to which the message is being sent. The generated id must not be more than 128 characters, and can contain alphanumeric characters and punctuation (``!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~``).
+Custom deduplicators are created by registering a new prefixed alias in the IoC. This alias should resolve to a new object instance that implements the `ShiftOneLabs\LaravelSqsFifoQueue\Contracts\Queue\Deduplicator` contract. You can either define a new class that implements this contract, or you can create a new `ShiftOneLabs\LaravelSqsFifoQueue\Queue\Deduplicators\Callback` instance, which takes a `Closure` that performs the deduplication logic. The defined `Closure` should take two parameters: `$payload` and `$queue`, where `$payload` is the `json_encoded()` message to send to the queue, and `$queue` is the name of the queue to which the message is being sent. The generated id must not be more than 128 characters, and can contain alphanumeric characters and punctuation (``!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~``). Additionally, AWS requires a string type. To prevent AWS errors, the result will be passed through `strval()` before being sent to AWS.
 
 So, for example, if you wanted to create a `random` deduplicator that would randomly select some jobs to be duplicates, you could add the following line in the `register()` method of your `AppServiceProvider`: