Update README.md

Add missing import from example

README.md

@@ -45,6 +45,7 @@ pip install diffusers transformers accelerate scipy safetensors
 Running the pipeline (if you don't swap the scheduler it will run with the default DDIM, in this example we are swapping it to EulerDiscreteScheduler):
 
 ```python
+import torch
 from diffusers import StableDiffusionPipeline, EulerDiscreteScheduler
 
 model_id = "stabilityai/stable-diffusion-2"