Add option to specify additional game versions (closes #25)

core/pack.go

@@ -26,6 +26,7 @@ type Pack struct {
 	Client   map[string]toml.Primitive         `toml:"client"`
 	Server   map[string]toml.Primitive         `toml:"server"`
 	Export   map[string]map[string]interface{} `toml:"export"`
+	Options  map[string]interface{}            `toml:"options"`
 }
 
 // LoadPack loads the modpack metadata to a Pack struct
@@ -35,6 +36,14 @@ func LoadPack() (Pack, error) {
 		return Pack{}, err
 	}
 
+	// Read options into viper
+	if modpack.Options != nil {
+		err := viper.MergeConfigMap(modpack.Options)
+		if err != nil {
+			return Pack{}, err
+		}
+	}
+
 	if len(modpack.Index.File) == 0 {
 		modpack.Index.File = "index.toml"
 	}