Project structure refactor:

- Change package name general_server to gateway
- Changing the structure of directories and packages
- Adding vendor to the project

vendor/github.com/spf13/viper/experimental.go

@@ -0,0 +1,8 @@
+package viper
+
+// ExperimentalBindStruct tells Viper to use the new bind struct feature.
+func ExperimentalBindStruct() Option {
+	return optionFunc(func(v *Viper) {
+		v.experimentalBindStruct = true
+	})
+}