Add example for `ioredis` package

[better-salmon]

The ioredis package has a different API than redis. A new page is needed to guide migration between these two packages.

[MauriceArikoglu]

I would not recommend to copy the description from two other lib's documentations. Leads to confusion if the library would change.

Instead I would argue it's more effective for you and the users if we'd describe a schema for initializing, storing and retrieving data. Through a generic description, other storage solutions could become viable as well.

[better-salmon]

Look at the Creating a Custom Handler guide to learn how to build a handler for ioredis or any other Redis client.