BuildMigrations - Instantiate a list of migrations from the contents of the provided files.

MARK: - Return `true` if the schemaTable is found and has no rows.

MARK: - Returns `true` if the schemaTable is found in the database.

MatchingFiles - Finds all files that statisfy a regex in the specified directory.

Validate - Runs validations on a list of migrations.

Runner: Responsible for running and reverting migrations.