How to use custom resolver implementation

I am trying to figure out how to use an existing resolver implementation. But when I run `go run github.com/99designs/gqlgen generate`, it overwrites the implementation in the `schema.resolvers.go` file.

I am using [this](https://github.com/nrfta/go-paging) package to add pagination to my GraphQL server.

I add the following to my `gqlgen.yaml` file:

```
models:
PageArgs:
model: github.com/nrfta/go-paging.PageArgs

PageInfo:
model: github.com/nrfta/go-paging.PageInfo
```

This is what is inside my `resolver.go`:

```
package graph

//go:generate go run github.com/99designs/gqlgen generate

import (
"github.com/nrfta/go-paging"
"github.com/gobuffalo/pop/v6"
)

// This file will not be regenerated automatically.
//
// It serves as dependency injection for your app, add any dependencies you require here.

type Resolver struct {
db *pop.Connection
}

func (r *Resolver) PageInfo() paging.PageInfoResolver {
return paging.NewPageInfoResolver()
}
```

When I run `go run github.com/99designs/gqlgen generate`, I would expect my `schema.resolvers.go` to *not* contain the auto-generated `pageInfoResolver` struct `PageInfo()` method, since I have already provided an implementation. However, they get generated, and I get the following error:

```
validation failed: packages.Load: /home/wheeler/Repositories/.../graph/schema.resolvers.go:70:20: method Resolver.PageInfo already declared at /home/wheeler/Repositories/.../graph/resolver.go:18:20

exit status 1
graph/resolver.go:3: running "go": exit status 1
```

How do I get gqlgen to stop auto-generating the methods that return the sub-resolvers if the methods are already defined?