internal/gaby: actually run github.Add

I don't know why but currently gabby does not call github.Add.
And make github.Add no-op if the project is already present in DB
(like CL 627778)

For #51

Change-Id: I9d3760bad50186a2f03e20f46d76ef164ac675f3
Reviewed-on: https://go-review.googlesource.com/c/oscar/+/629355
Reviewed-by: Zvonimir Pavlinovic <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>

internal/gaby/main.go

@@ -122,6 +122,11 @@ func main() {
 	defer shutdown()
 
 	g.github = github.New(g.slog, g.db, g.secret, g.http)
+	for _, project := range g.githubProjects {
+		if err := g.github.Add(project); err != nil {
+			log.Fatalf("github.Add failed: %v", err)
+		}
+	}
 	g.disc = discussion.New(g.ctx, g.slog, g.secret, g.db)
 	for _, project := range g.githubProjects {
 		if err := g.disc.Add(project); err != nil {

internal/github/sync.go

@@ -155,11 +155,11 @@ func (proj *projectSync) store(db storage.DB) {
 // to the database.
 // It only adds the project sync metadata.
 // The initial data fetch does not happen until [Sync] or [SyncProject] is called.
-// Add returns an error if the project has already been added.
+// If the project is already present, Add does nothing and returns nil.
 func (c *Client) Add(project string) error {
 	key := o(syncProjectKind, project)
 	if _, ok := c.db.Get(key); ok {
-		return fmt.Errorf("github.Add: already added: %q", project)
+		return nil
 	}
 	c.db.Set(key, storage.JSON(&projectSync{Name: project}))
 	return nil