Ship Modin with Ray. (#3109)

python/ray/__init__.py

@@ -46,6 +46,9 @@ except ImportError as e:
             e.args += (helpful_message, )
     raise
 
+modin_path = os.path.join(os.path.abspath(os.path.dirname(__file__)), "modin")
+sys.path.insert(0, modin_path)
+
 from ray.raylet import ObjectID, _config  # noqa: E402
 from ray.profiling import profile  # noqa: E402
 from ray.worker import (error_info, init, connect, disconnect, get, put, wait,