make app reusable for other models

app.py

@@ -1,11 +1,12 @@
 import gradio as gr
 import spaces
 import torch
+import os
 from compel import Compel, ReturnedEmbeddingsType
 from diffusers import DiffusionPipeline
 
 
-model_name = 'UnfilteredAI/NSFW-gen-v2'
+model_name = os.environ.get('MODEL_NAME', 'UnfilteredAI/NSFW-gen-v2')
 pipe = DiffusionPipeline.from_pretrained(
     model_name,
     torch_dtype=torch.float16