Be explicit in what is used, db or trades

freqtrade/arguments.py

@@ -515,3 +515,10 @@ class Arguments(object):
             default=750,
             type=int,
         )
+        parser.add_argument(
+            '--trade-source',
+            help='Specify the source for trades (Can be DB or file (backtest file)) Default: %(default)s',
+            dest='trade_source',
+            default="file",
+            choices=["DB", "file"]
+        )

freqtrade/configuration.py

@@ -358,7 +358,8 @@ class Configuration(object):
 
         self._args_to_config(config, argname='plot_limit',
                              logstring='Limiting plot to: {}')
-
+        self._args_to_config(config, argname='trade_source',
+                             logstring='Using trades from: {}')
         return config
 
     def _validate_config_schema(self, conf: Dict[str, Any]) -> Dict[str, Any]: