Add database schema, ERD, and repository layer

internal/database/db.go

@@ -0,0 +1,32 @@
+package database
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+	"github.com/rs/zerolog/log"
+)
+
+type DB struct {
+	Pool *pgxpool.Pool
+}
+
+func New(ctx context.Context, databaseURL string) (*DB, error) {
+	pool, err := pgxpool.New(ctx, databaseURL)
+	if err != nil {
+		return nil, fmt.Errorf("connecting to database: %w", err)
+	}
+
+	if err := pool.Ping(ctx); err != nil {
+		return nil, fmt.Errorf("pinging database: %w", err)
+	}
+
+	log.Info().Str("url", databaseURL).Msg("database connected")
+
+	return &DB{Pool: pool}, nil
+}
+
+func (db *DB) Close() {
+	db.Pool.Close()
+}