Add database driver and config module

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

config/types.go

@@ -0,0 +1,20 @@
+package config
+
+type config struct {
+	Server   server   `yaml:"server"`
+	Database database `yaml:"database"`
+}
+
+type server struct {
+	Address    string `yaml:"address"`
+	DebugMode  bool   `yaml:"debug_mode"`
+	FileLogger bool   `yaml:"file_logger"`
+}
+
+type database struct {
+	Type     string `yaml:"type"`
+	Host     string `yaml:"host"`
+	Name     string `yaml:"name"`
+	Username string `yaml:"username"`
+	Password string `yaml:"password"`
+}