address review comments

config.go

@@ -8,6 +8,12 @@ import (
 	"io/ioutil"
 )
 
+const (
+	// Globals are applicable to all rules and used for general
+	// configuration settings for gas.
+	Globals = "global"
+)
+
 // Config is used to provide configuration and customization to each of the rules.
 type Config map[string]interface{}
 
@@ -16,7 +22,7 @@ type Config map[string]interface{}
 // or from a *os.File.
 func NewConfig() Config {
 	cfg := make(Config)
-	cfg["global"] = make(map[string]string)
+	cfg[Globals] = make(map[string]string)
 	return cfg
 }
 
@@ -60,7 +66,7 @@ func (c Config) Set(section string, value interface{}) {
 
 // GetGlobal returns value associated with global configuration option
 func (c Config) GetGlobal(option string) (string, error) {
-	if globals, ok := c["global"]; ok {
+	if globals, ok := c[Globals]; ok {
 		if settings, ok := globals.(map[string]string); ok {
 			if value, ok := settings[option]; ok {
 				return value, nil
@@ -74,7 +80,7 @@ func (c Config) GetGlobal(option string) (string, error) {
 
 // SetGlobal associates a value with a global configuration ooption
 func (c Config) SetGlobal(option, value string) {
-	if globals, ok := c["global"]; ok {
+	if globals, ok := c[Globals]; ok {
 		if settings, ok := globals.(map[string]string); ok {
 			settings[option] = value
 		}