Add kelseyhightower/envconfig to configurations sections
@@ -226,6 +226,7 @@ Please take a quick gander at the [contribution guidelines](https://github.com/a
* [ingo](https://github.com/schachmat/ingo) - Flags persisted in an ini-like config file.
* [ini](https://github.com/go-ini/ini) - Go package to read and write INI files.
* [joshbetz/config](https://github.com/joshbetz/config) - Small configuration library for Go that parses environment variables, JSON files, and reloads automatically on SIGHUP.
+* [kelseyhightower/envconfig](https://github.com/kelseyhightower/envconfig) - Go library for managing configuration data from environment variables.
* [mini](https://github.com/sasbury/mini) - Golang package for parsing ini-style configuration files.
* [store](https://github.com/tucnak/store) - Lightweight configuration manager for Go.
* [viper](https://github.com/spf13/viper) - Go configuration with fangs.
