Support bytes as SECURITY_KEY

auth.py

@@ -59,7 +59,9 @@ class UserManager:
 
 class SecurityManager:
     def __init__(self, key, max_duration=300):
-        self.maccer = hmac.new(key.encode("utf-8"), digestmod=hashlib.sha512)
+        if isinstance(key, str):
+            key = key.encode("utf-8")
+        self.maccer = hmac.new(key, digestmod=hashlib.sha512)
         self.max_duration = max_duration
 
     def hash_user(self, user):
@@ -99,7 +101,7 @@ class StaticUserManager:
 
     def __repr__(self):
         users = [
-            (username, self.passwords[username], self.groups[username])
+            (username, self.passwords[username], self.group_map[username])
             for username in self.passwords
         ]
         return "StaticUserManager({})".format(users)