v1.5.0

• Fixes #69: Added DB.TableMapper to support using common prefix/suffix with table names when performing model-based queries. (Thanks to @kPshi !)
• Fixes #70: Fixed the rawSQL generated by Upsert for PostgreSQL DB. (Thanks to @vasilistefanenko !)
• Added DB.WithContext() to support getting a DB instance with a context. This is useful for creating queries with context.