IN operator fails when nil is passed as the array to search in

[GonzaRodriguez]

I've noticed that the in operator is failing when receiving nil values as the array.

Context:

We have been using JSONLogic for a couple of years now to evaluate rules on serialized objects at runtime. Most of the time, we don't know the actual values of the variables used in the rules since they are built by serializing objects retrieved from our database.

Current behavior:

When the variable (array to search in) doesn't exist in the object, a nil value is passed as the array, so in that case the gem is failing due to a NoMethodError: undefined method include?' for nil:NilClass`.

Here you can see an example:

rule = {"in" => ["value_to_search", {"var" => "array"}]}
variable = {"array" => nil} (Consider that nil is the value after some processing at runtime)

JSONLogic.apply(rule, variable)

The output:

[GonzaRodriguez]

@bhgames I will be pleased to open a PR to fix it. Please let me know if it makes sense for you.