No unified way of setting up SQLAlchemy sessions

[guilhermelou]

The session setup has to be done twice and ideally there should be a single point of contact for it.
As of now, there's a session setup for the Dataloader injected in the context and one for the relay connections, e.g.:

Session Setup For Dataloaders

# context is expected to have an instance of StrawberrySQLAlchemyLoader
class CustomGraphQLView(GraphQLView):
    def get_context(self):
        return {
            "sqlalchemy_loader": StrawberrySQLAlchemyLoader(bind=YOUR_SESSION),
        }

Session Setup For Relay

@mapper.type(fruit_table)
class Fruit(relay.Node):
    id: relay.NodeID[int]

@strawberry.type
class Query:
    fruits: relay.ListConnection[Fruit] = connection(sessionmaker=sessionmaker)

The issue had already been spotted by the author on this comment: #65 (comment) and discussed on a community-chat session.