Custom Pipelines handled through Appsync

**Is your feature request related to a problem? Please describe.**
A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]

In generation 1, I can create custom mutations + queries, just by stating the name, input and return type. Then i can handle the custom logic, "data pipelines" invoking other lambda functions inside the appsync console.

In generation 2, it seems like you have to do all that logic in template files somewhere else and maybe its the same, but it is confusing for me.

**Describe the solution you'd like**
A clear and concise description of what you want to happen.
I just want a way to add in my custom mutation, specify the input, and the output like I did in generation 1, and maybe there is a key word or some other attribute that I add that lets it know that there doesn't have to be a specified resolver, and that appsync will handle the logic for it.

**Describe alternatives you've considered**
A clear and concise description of any alternative solutions or features you've considered.

I have tried to figure out what the current template thing is but the documentation is a little sparse and doesn't go over how you would invoke a lambda function or build it into a pipeline of lambda functions.

**Additional context**
Add any other context or screenshots about the feature request here.

one more annoying thing is that in gen1, if you create a lambda endpoint resolver a different way( in the function part) it sometimes clears out the custom logic that you did in appsync.