Add note about casting ttl values to integer

[jamesgecko]

The changelog mentions that TTL values are cast to int, but this information is not present in the types section of the README. Adding the info with an example.

[byroot]

That's not correct. There is no such thing as TTL values, here you are passing an ActiveSupport::Duration instance. And there is no special handling about them.

[jamesgecko]

Sorry, I was trying to copy the language from the changelog, but maybe there's a better way to state it.

The Integer casting added to various duration-related functions in 5.0.4 does operate on ActiveRecord::Duration because of duck typing; the cast returns the duration in seconds as an integer. I can change the example if you'd prefer something less Rails-y?

[byroot]

Yes. But also note you are linking to the redis gem, which define a speciific method for each command, so it know what the expected type is, so it can cast to integer where an integer is expected.

Here we're commenting in redis-client, which is lower level and doesn't know anything about command signatures and what the expected types are, hence why it only as very simplistic and generic casting rules.