plugins: Create availablePlugins config file if it does not exist.

fs/rc/webgui/plugins.go

@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"net/http/httputil"
 	"net/url"
+	"os"
 	"path/filepath"
 	"regexp"
 	"strings"
@@ -97,15 +98,25 @@ func (p *Plugins) readFromFile() (err error) {
 		return err
 	}
 	availablePluginsJSON := filepath.Join(pluginsConfigPath, p.fileName)
+	_, err = os.Stat(availablePluginsJSON)
+	if err == nil {
 		data, err := ioutil.ReadFile(availablePluginsJSON)
 		if err != nil {
-		// create a file ?
+			return err
 		}
 		err = json.Unmarshal(data, &p)
 		if err != nil {
 			fs.Logf(nil, "%s", err)
 		}
 		return nil
+	} else if os.IsNotExist(err) {
+		// path does not exist
+		err = p.writeToFile()
+		if err != nil {
+			return err
+		}
+	}
+	return nil
 }
 
 func (p *Plugins) addPlugin(pluginName string, packageJSONPath string) (err error) {