fix plugin config

plugins/emqttd_auth_mysql/README.md

@@ -1,11 +1,11 @@
+
 ## Overview
 
 Authentication with user table of MySQL database.
 
 ## etc/plugin.config
 
-```erlang
-[
+```
  {emysql, [
     {pool,      4},
     {host,      "localhost"},
@@ -24,7 +24,6 @@ Authentication with user table of MySQL database.
         {password, password}
     ]}
  ]}
-].
 ```
 
 ## Users Table(Demo)

plugins/emqttd_auth_mysql/etc/plugin.config

@@ -1,5 +1,4 @@
-[
- {emysql, [
+{emysql, [
    {pool,      4},
    {host,      "localhost"},
    {port,      3306},
@@ -7,12 +6,11 @@
    {password,  "public"},
    {database,  "mqtt"},
    {encoding,  utf8}
- ]},
- {emqttd_auth_mysql, [
+]},
+{emqttd_auth_mysql, [
    {users_table, mqtt_users},
    {field_mapper, [
        {username, username},
        {password, password, plain}
    ]}
- ]}
-].
+]}