Use Mongoose as the model layer + convert simpl-schema to mongoose

[eric-burel]

That would be a big work but it would bring significant improvements:

• compatibility with tooling meant for Mongoose schemas, eg Forest Admin. We we would probably need not only to generate the schema dynamically, but also to export it as a file (like we can do with the graphql schema)
• onCreate, onUpdate etc., and maybe callbacks, could be moved from the controller layer (GraphQL) to the model layer (Mongo/Mongoose). This would make direct call to the database easier server side. Currently you need to use the mutator by hand, because it is in charge of running callbacks and all, and create the context manually, it feels messy.
• demeteorization, we would be able to use a better maintained and more common API for collections

Maybe it would be possible to get help from the community on this, since a simpl-schema / mongoose converter could be interesting for others Meteor users too.

Note that similar pattern could make sense for SQL too, by converting the simple schema to Knex calls for example.

[gland2015]

I think it's good，simpl-schema hasn't been updated for a long time.

[eric-burel]

It wouldn't replace simpl-schema though, because we need a schema system that is also available client side. I think more about a simpl-schema/mongoose converter. Also I think simpl-schema is rather stable, hence the lack of updates, it's not necessarily an issue.