Ability to customize type on partition key & setting created_at as range key.

[rahul342]

I am interested in exploring and building two new features which are currently not supported. I am hoping to discuss here before submitting code to check if this is something we would like to have and what the API design looks like.

1. Ability to customize type of partition key.

Currently you can define a new hash_key with table but are not allowed to specify a type.
OR
If you want a different type, the comments suggest to explicitly define id with the new type. This still prints warning because id is already defined.
I am proposing

• Add a new hash_key_type to be defined with table
• Allow overriding id without warning.

2. Ability to specify one of the timestamp fields as range_key

Using timestamps of created_at/updated_at as range_key is fairly common. Dynamoid offers a neat way to automagically add and sync created_at/update_at timestamps, but doesn't allow to cleanly use one of auto-added fields as the range key.
If created_at is specified as range param in conjunction with timestamps options , it will print warning.
If you turn off timestamps, you don't get the neat functionality of having created_at, updated_at maintained for you.
I am not sure what the API of this one should look like, we can add either extra options with timestamps or allow setting range_key but the field has to be declared separately.