docs(users.md): add user rate limits to docs

docs/my-website/docs/proxy/users.md

@@ -1,11 +1,13 @@
-# Set budgets per user 
-
-LiteLLM exposes a `/user/new` endpoint to create budgets for users, that persist across multiple keys. 
+# Set Budgets + Rate Limits per user 
 
 Requirements: 
 
 - Need to a postgres database (e.g. [Supabase](https://supabase.com/), [Neon](https://neon.tech/), etc)
 
+
+## Set Budgets
+LiteLLM exposes a `/user/new` endpoint to create budgets for users, that persist across multiple keys. 
+
 This is documented in the swagger (live on your server root endpoint - e.g. `http://0.0.0.0:8000/`). Here's an example request. 
 
 ```curl 
@@ -28,3 +30,13 @@ The request is a normal `/key/generate` request body + a `max_budget` field.
 ```
 
 
+## Set Rate Limits 
+
+Set max parallel requests a user can make, when you create user keys - `/key/generate`. 
+
+```bash
+curl --location 'http://0.0.0.0:8000/key/generate' \
+--header 'Authorization: Bearer sk-1234' \
+--header 'Content-Type: application/json' \
+--data '{"duration": "20m", "max_parallel_requests": 1}' # 👈 max parallel requests = 1
+```