Define Context as Immutable

[tgallice]

I think the Context must be immutable to prevent side effects. This way we can track all context modifications and why not provide a history ?

[hfinck]

Can you elaborate on this? At least within the action mapping we want to modify context data, since this is what helps wit.ai to predict the next actions.

[tgallice]

What I mean it's we should not update the current Context but return a new Context with previous value and new one added. It's just to prevent side effets.