feat: add webhook endpoint to support syncing clerk user data into users table

convex/schema.ts

@@ -0,0 +1,8 @@
+import { defineSchema, defineTable } from 'convex/server';
+import { v } from 'convex/values';
+
+export default defineSchema({
+  users: defineTable({
+    clerkUser: v.any(),
+  }).index('by_clerk_id', ['clerkUser.id']),
+});