Added short and exit_short to strategy

freqtrade/enums/signaltype.py

@@ -7,6 +7,8 @@ class SignalType(Enum):
     """
     BUY = "buy"
     SELL = "sell"
+    SHORT = "short"
+    EXIT_SHORT = "exit_short"
 
 
 class SignalTagType(Enum):
@@ -14,3 +16,4 @@ class SignalTagType(Enum):
     Enum for signal columns
     """
     BUY_TAG = "buy_tag"
+    SELL_TAG = "sell_tag"