--- a/log4-hi-mode.el	Thu Mar 30 00:22:53 2017 +0300
+++ b/log4-hi-mode.el	Thu Mar 30 00:24:42 2017 +0300
@@ -5,25 +5,35 @@
 
 ;;; Code:
 
+(defgroup log4-hi nil
+  "`log4-hi-mode' mode for highlighting logs."
+  :prefix "log4-hi-"
+  :group 'text)
+
 (defface log4-hi-error-face
   '((t :inherit error))
-  "Face for critical message.")
+  "Face for critical message."
+  :group 'log4-hi)
 
 (defface log4-hi-warn-face
   '((t :inherit warning))
-  "Face for urgent message.")
+  "Face for urgent message."
+  :group 'log4-hi)
 
 (defface log4-hi-info-face
   '((t :inherit success))
-  "Face for informational message.")
+  "Face for informational message."
+  :group 'log4-hi)
 
 (defface log4-hi-func-face
   '((t :inherit font-lock-function-name-face))
-  "Face for functions in trace.")
+  "Face for functions in trace."
+  :group 'log4-hi)
 
 (defface log4-hi-time-face
   '((t :inherit font-lock-builtin-face))
-  "Face for time.")
+  "Face for time."
+  :group 'log4-hi)
 
 (defvar log4-hi-keywords
   '(("FATAL\\|ERROR" . 'log4-hi-error-face)