add nullstore that does absolutely nothing.

nullstore/README.md

@@ -0,0 +1,2 @@
+`nullstore` is an eventstore that doesn't actually do anything.
+It doesn't store anything, it doesn't return anything.

nullstore/lib.go

@@ -0,0 +1,32 @@
+package nullstore
+
+import (
+	"context"
+
+	"github.com/fiatjaf/eventstore"
+	"github.com/nbd-wtf/go-nostr"
+)
+
+var _ eventstore.Store = (*NullStore)(nil)
+
+type NullStore struct{}
+
+func (b *NullStore) Init() error {
+	return nil
+}
+
+func (b NullStore) Close() {}
+
+func (b NullStore) DeleteEvent(ctx context.Context, evt *nostr.Event) error {
+	return nil
+}
+
+func (b NullStore) QueryEvents(ctx context.Context, filter nostr.Filter) (chan *nostr.Event, error) {
+	ch := make(chan *nostr.Event)
+	close(ch)
+	return ch, nil
+}
+
+func (b NullStore) SaveEvent(ctx context.Context, evt *nostr.Event) error {
+	return nil
+}