Luís Murta
19974a5f44
Adds the database abstraction layer (DAL) with a Transactions method and a Connection object to encapsulate the DB open connection. Includes a DAL unit test using the go-sqlmock library. Connection to a PostgreSQL database using environment variables to store the secrets. Overall, with the /transactions endpoint requesting directly to the DB, this patch finish the tracer bullet project. Issues #1, #5, #6 and #7