Improves documentation (#13)

* Documents all env variables and adds an example project

* Adds godoc comments

* Fixed package naming issue

config/main.go

@@ -1,6 +1,7 @@
 // Package config defines the env configuration variables
 package config
 
+// Config defines all the configuration variables for the golang-base-project
 type Config struct {
 	Port              string
 	CookieSecret      string