[feat] pass connection object to newAdapter

[node-casbin]

[feat] pass connection object to newAdapter

[hsluoyz]

@onichandame great idea. Can you make a PR to add a new constructor to accept conn as arg?

[onichandame]

The way how TypeORM manages tables(entities) is quite different from the MongDB's approach. In MongoDB, the tables(collections) are implicitly created the first time they are used, whereas TypeORM needs to provision tables(entities) before setting up the connection.

Because we have to allow each module to maintain the tables they each need, in TypeORM it is better to let each module handle their own connection with the schema they each use.

An approach to what I originally want is to allow each module to add tables(entities) to the same connection so we end up with a single connection for all modules. To achieve this, there are 2 options:

1. feed all entities to the connection constructor
2. pass the same connection to every module. Each module then adds its entities into the same connection

The first option is quite hard to maintain. The second option is not possible yet. This issue of TypeORM is related but no progress has been seen.

So the best choice, for now, is to manage the common connection options at one place and let modules to handle their connections themselves.