(Issue#45) Scope Configuration doesn't work with Postgres

[oleksm]

Hi,
I noticed same issue described by @Manny651 when tried using scope config.json as described in issue #45 . The problem is that 'database' property attempted to use as a schema despite of warning message that it is going to be ignored, and 'schema' property ignored at the same time. More importantly, SET search_path TO databaseName statement contains tildas which is not correct postgres syntax.
The change am I proposing is:

1. Fix SET search_path TO schema syntax
2. Use 'schema' property instead of 'database' inside switchDatabase method.
3. When switching db, preserve original schema in search path so migrations table is still available
   Please approve PR.

[oleksm]

@wzrdtales Could you please approve pr?

[wzrdtales]

Hey, thanks for pinging me again and thank you for your contribution, I will review it today.

[wzrdtales]

looks good in general, however the pg driver is a dependency to a lot of other drivers, so SET search_path TO %s,%s this alteration of the search path could impact them. I will have to validate a few targets before I can merge this.

[wzrdtales]

this will certainly break a lot of dbs connected using the pg wire protocol, so that can't just be overwritten here (also in pg dbs exist though