diff --git a/config/config.go b/config/config.go
index 0eb46cc..bf9b746 100644
--- a/config/config.go
+++ b/config/config.go
@@ -25,7 +25,8 @@ type Server struct {
 }
 
 type Log struct {
-	Path string `yaml:"path"`
+	WriteToFile bool   `yaml:"write_to_file"`
+	Path        string `yaml:"path"`
 }
 
 type User struct {
@@ -38,6 +39,18 @@ func (conf *Config) BasicCheck() error {
 	if len(conf.Users) <= 0 {
 		return errors.New("invalid user length")
 	}
+
+	for _, u := range conf.Users {
+		allCmds := false
+		for _, c := range u.Cmds {
+			if c == "*" {
+				allCmds = true
+			}
+		}
+		if allCmds && len(u.Cmds) > 1 {
+			return errors.New("can't have all cmds and specific cmd at same time")
+		}
+	}
 	return nil
 }
 
@@ -48,7 +61,8 @@ func DefaultConfig() *Config {
 			Port: "7070",
 		},
 		Log: Log{
-			Path: "ttrace.log",
+			WriteToFile: true,
+			Path:        "ttrace.log",
 		},
 		Name: "time_trace",
 	}
diff --git a/config/config.yaml b/config/config.yaml
index c55b8c7..4dfaf2a 100644
--- a/config/config.yaml
+++ b/config/config.yaml
@@ -5,6 +5,7 @@ server:
   port: "7070"
 
 log:
+  write_to_file: true
   path: ttrace.log
 
 users:
@@ -18,10 +19,10 @@ users:
 #   - name: root
 #     password: super_secret_password
 #     cmd:
-#       - * # all commands.
+#       - '*' # all commands.
 #   - name: developer
 #     password: secret_password
 #     cmd:
-#       - GET
-#       - PUSH
-#       - DEL
\ No newline at end of file
+#       - 'GET'
+#       - 'PUSH'
+#       - 'DEL'
\ No newline at end of file
diff --git a/config/config_test.go b/config/config_test.go
index cf8b40b..928dacb 100644
--- a/config/config_test.go
+++ b/config/config_test.go
@@ -53,4 +53,9 @@ func TestBasicCheck(t *testing.T) {
 	c.Users = []User{}
 	err = c.BasicCheck()
 	assert.Error(t, errors.New("invalid user length"), err)
+
+	c.Users = []User{DefaultConfig().Users[0]}
+	c.Users[0].Cmds = []string{"*", "GET"}
+	err = c.BasicCheck()
+	assert.Error(t, errors.New("can't have all cmds and specific cmd at same time"), err)
 }
diff --git a/doc/config/.keep b/doc/config/.keep
deleted file mode 100644
index e69de29..0000000
diff --git a/doc/config/config.md b/doc/config/config.md
new file mode 100644
index 0000000..f8c992d
--- /dev/null
+++ b/doc/config/config.md
@@ -0,0 +1,71 @@
+# Config
+
+In this part of documentation we are going to explain config in ttrace.
+
+### config file
+
+In ttrace we have config in `yaml` format, you can see default config example [here](../../config/config.yaml).
+Now we explain each part of config one by one.
+
+#### name
+
+First of all we have a name, which is name of instance you are running (you can use it on application layer and get it by commands).
+This is name field in `config.yaml`:
+
+```yml
+name: time_trace
+```
+
+#### server
+
+In server part you can config this two: which ip? which port? for listening and serving the TCP server.
+
+This is how it looks in `config.yaml`:
+
+```yml
+server:
+  listen: localhost
+  port: "7070"
+```
+
+#### log
+
+This part will help you to config log stuff (levels, saving path and...).
+
+How it looks in `config.yaml`:
+
+```yml
+log:
+  write_to_file: true
+  path: ttrace.log
+```
+
+#### users
+
+In users part, you define who can access the database and set permission for them. `name` and `password` field is user pass for connecting (required in `CON` command).
+
+In `cmds` you provide which command in [TQL](../TQL/) they have access to. It can be a list of commands or just a `'*'` which means all.
+Also the `CON` command is open for everyone.
+
+example:
+
+```yml
+users:
+- name: root
+  password: super_secret_password
+  cmds:
+  - '*'
+
+# Also you can use this for multiple users and limited commands
+# users:
+#   - name: root
+#     password: super_secret_password
+#     cmd:
+#       - '*' # all commands.
+#   - name: developer
+#     password: secret_password
+#     cmd:
+#       - 'GET'
+#       - 'PUSH'
+#       - 'DEL'
+```