Merge pull request #78 from hiroki-sawano/fix-change-password

Fix failed to change password due to compatibility issues with JupyterHub 1.0.0

nativeauthenticator/handlers.py

@@ -123,7 +123,7 @@ async def get(self):
 
     @web.authenticated
     async def post(self):
-        user = self.get_current_user()
+        user = await self.get_current_user()
         new_password = self.get_body_argument('password', strip=False)
         self.authenticator.change_password(user.name, new_password)