feat: add OpenAPI definition

backend/routes.go

@@ -1,6 +1,8 @@
 package backend
 
 import (
+	"net/http"
+
 	"codeberg.org/u1f320/pronouns.cc/backend/routes/auth"
 	"codeberg.org/u1f320/pronouns.cc/backend/routes/bot"
 	"codeberg.org/u1f320/pronouns.cc/backend/routes/member"
@@ -9,8 +11,14 @@ import (
 	"codeberg.org/u1f320/pronouns.cc/backend/routes/user"
 	"codeberg.org/u1f320/pronouns.cc/backend/server"
 	"github.com/go-chi/chi/v5"
+	"github.com/go-chi/render"
+
+	_ "embed"
 )
 
+//go:embed openapi.html
+var openapi string
+
 // mountRoutes mounts all API routes on the server's router.
 // they are all mounted under /v1/
 func mountRoutes(s *server.Server) {
@@ -23,4 +31,9 @@ func mountRoutes(s *server.Server) {
 		meta.Mount(s, r)
 		mod.Mount(s, r)
 	})
+
+	// API docs
+	s.Router.Get("/", func(w http.ResponseWriter, r *http.Request) {
+		render.HTML(w, r, openapi)
+	})
 }