Add Schema to postgres connections

[josephmancuso]

Describe the feature as you'd like to see it
Should be able to specify a schema at the connection level (which would then be able to be modified on the fly)

What do we currently have to do now?
We actually cannot specify the schema at all. It will always default to the default schema

Additional context
In the future this will need to be changed via a middleware so schemas can change based on he hostname or something

• Is this a breaking change? - no should not be

[josephmancuso]

A few different use cases for this:

• 1. Changing the schema on the fly. Will need to be done using a set_schema on the model / query builder

User.set_schema("schema2").get()

• 2. Changing the schema to use a single schema in the config:

"postgres": {
        "driver": "postgres",
        "host": os.getenv("POSTGRES_DATABASE_HOST"),
        "..",
        "schema": "schema2",
    },

• 3. On the migrations it need to be able to set a schema to migrate to a specific schema
• Be able to set the search path during a request on the middleware

[josephmancuso]

1. would need a middleware to switch the schema for each subdomain request
2. would need a table on the public schema that would store all the tenants
3. would need a custom migration command to fetch all tenants in the tenant table and run the migrations for each schema