Fix for #142

Former-commit-id: e90d48532a52279e1dc201a4a608d7d4feee924f [formerly d2b7a5372ad7bb2b664f205cf0b7b82cd4741cc4] [formerly eec7d5cf1cfc2f7f8351bbac0787de8a53b5e9d8 [formerly 40b31bd291]]
Former-commit-id: dbfbc3c849a526345848c56be7db48de0eadba5d [formerly 287567052912b6da7bc379bc690a7006d81d0701]
Former-commit-id: 8d42c024c830c2f783cfc75f06b76b355029cca8

users.go

@@ -263,8 +263,15 @@ func usersPutHandler(c *RequestContext, w http.ResponseWriter, r *http.Request)
 		u.Commands = []string{}
 	}
 
-	ouser, ok := c.FM.Users[u.Username]
-	if !ok {
+	var ouser *User
+	for _, user := range c.FM.Users {
+		if user.ID == id {
+			ouser = user
+			break
+		}
+	}
+
+	if ouser == nil {
 		return http.StatusNotFound, nil
 	}
 
@@ -292,6 +299,12 @@ func usersPutHandler(c *RequestContext, w http.ResponseWriter, r *http.Request)
 		return http.StatusInternalServerError, err
 	}
 
+	// If the user changed the username, delete the old user
+	// from the in-memory user map.
+	if ouser.Username != u.Username {
+		delete(c.FM.Users, ouser.Username)
+	}
+
 	c.FM.Users[u.Username] = &u
 	return http.StatusOK, nil
 }