Config file
Path at type safe config
the { @code Enum} value at the requested path of the requested enum class
com.typesafe.config.ConfigException.Missing
if value is absent or null
com.typesafe.config.ConfigException.WrongType
if value is not convertible to an Enum
OS environment variable key
Type safe configuration key
configuration value
OS environment variable key
Optional environment variable value
Helper object that loads configuration
scala.RuntimeException
if required configuration not specified(FACEBOOK_CLIENT_ID, FACEBOOK_REDIRECT_URI, FACEBOOK_APP_SECRET)