[booster] init module structure and definition (#3056)

colossalai/booster/accelerator.py

@@ -0,0 +1,14 @@
+import torch
+import torch.nn as nn
+
+__all__ = ['Accelerator']
+
+
+class Accelerator:
+
+    def __init__(self, device: torch.device):
+        self.device = device
+
+    def setup_model(self, model: nn.Module) -> nn.Module:
+        # TODO: implement this method
+        pass