Small error in docs

[d-sooter]

First of all great product.

i think there is a small mistake in the coding if i am not mistaken it should be product.giftCard=== params.giftCard

https://github.com/CacheControl/json-rules-engine/blob/90272d61ed7bea8b7d4000305511e932490d2e2e/examples/08-fact-comparison.js#L69

[mrcrumpy]

I feel like you are mistaken here. The productId in both objects is "giftCard" as a string.

https://github.com/CacheControl/json-rules-engine/blob/90272d61ed7bea8b7d4000305511e932490d2e2e/examples/08-fact-comparison.js#L91

https://github.com/CacheControl/json-rules-engine/blob/90272d61ed7bea8b7d4000305511e932490d2e2e/examples/08-fact-comparison.js#L44