Add jwt crypto module, support unit test for config module

Signed-off-by:  Asai Neko<sugar@sne.moe>

config/default.go

@@ -4,6 +4,7 @@ var serverDef = server{
 	Address:    ":8000",
 	DebugMode:  false,
 	FileLogger: false,
+	JwtSecret:  "something",
 }
 
 var databaseDef = database{