momento

diff --git a/database/middleware.go b/database/middleware.go
new file mode 100644
index 0000000000000000000000000000000000000000..2270eb661fab4f2d41e0d93e83231004bc50e8cb
--- /dev/null
+++ b/database/middleware.go
@@ -0,0 +1,70 @@
+package database
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"net/http"
+)
+
+var dbCtxKey = &contextKey{"database"}
+
+type contextKey struct {
+	name string
+}
+
+func Middleware(db *sql.DB) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			ctx := Context(r.Context(), db)
+			r = r.WithContext(ctx)
+			next.ServeHTTP(w, r)
+		})
+	}
+}
+
+func Context(ctx context.Context, db *sql.DB) context.Context {
+	return context.WithValue(ctx, dbCtxKey, db)
+}
+
+func ForContext(ctx context.Context) (*sql.Conn, error) {
+	raw, ok := ctx.Value(dbCtxKey).(*sql.DB)
+	if !ok {
+		panic(errors.New("Invalid database context"))
+	}
+	return raw.Conn(ctx)
+}
+
+func WithTx(ctx context.Context, opts *sql.TxOptions, fn func(tx *sql.Tx) error) error {
+	conn, err := ForContext(ctx)
+	if err != nil {
+		return err
+	}
+	defer conn.Close()
+
+	tx, err := conn.BeginTx(ctx, opts)
+	if err != nil {
+		return err
+	}
+
+	defer func() {
+		if r := recover(); r != nil {
+			tx.Rollback()
+			panic(r)
+		}
+	}()
+	err = fn(tx)
+
+	if err != nil {
+		err := tx.Rollback()
+		if err != nil && err != sql.ErrTxDone {
+			panic(err)
+		}
+	} else {
+		err := tx.Commit()
+		if err != nil && err != sql.ErrTxDone {
+			panic(err)
+		}
+	}
+	return err
+}