[IMPROVE] Allow multiple schema directories through one schema_version table

[zobayer1]

TL;DR

Current implementation do not distinguish among schema files for different projects. It would be a good feature to pass a prefix/suffix name through the configuration file that can handle separate versioning for them.

Design

Proposal

• Add a configuration field such as schema_name. If not provided, a random 4 letter string will be assigned.
• Add a column named schema_name in schema_version table.
• Concatenate schema_name 4 letter prefix with ID field to avoid multiple field query when searching by ID.
• All the other queries must add schema name prefix as a where clause too.

Alternatives considered

• Add a way to dynamically alter __tablename__ which is not a simple solution.