Merge pull request #819 from r0fls/817

convert environment vars to int if digits

sanic/config.py

@@ -201,4 +201,10 @@ class Config(dict):
         for k, v in os.environ.items():
             if k.startswith(SANIC_PREFIX):
                 _, config_key = k.split(SANIC_PREFIX, 1)
+                try:
+                    self[config_key] = int(v)
+                except ValueError:
+                    try:
+                        self[config_key] = float(v)
+                    except ValueError:
                         self[config_key] = v