Use overlay

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

overlays/spicetify-cli/user-colors.patch

@@ -0,0 +1,31 @@
+diff --git a/src/apply/apply.go b/src/apply/apply.go
+index 47f1346..47badab 100644
+--- a/src/apply/apply.go
++++ b/src/apply/apply.go
+@@ -2,6 +2,7 @@ package apply
+ 
+ import (
+ 	"fmt"
++	"errors"
+ 	"os"
+ 	"path/filepath"
+ 	"strings"
+@@ -65,10 +66,17 @@ func AdditionalOptions(appsFolderPath string, flags Flag) {
+ // To not use custom css, set `themeFolder` to blank string
+ // To use default color scheme, set `scheme` to `nil`
+ func UserCSS(appsFolderPath, themeFolder string, scheme map[string]string) {
++	colorsSrc := os.Getenv("COLORS_CSS_PATH")
+ 	colorsDest := filepath.Join(appsFolderPath, "xpui", "colors.css")
+-	if err := os.WriteFile(colorsDest, []byte(getColorCSS(scheme)), 0700); err != nil {
++
++	if len(colorsSrc) == 0 {
++		utils.Fatal(errors.New("COLORS_CSS_PATH environment variable is not set"))
++	}
++
++	if err := os.Symlink(colorsSrc, colorsDest); err != nil {
+ 		utils.Fatal(err)
+ 	}
++
+ 	cssDest := filepath.Join(appsFolderPath, "xpui", "user.css")
+ 	if err := os.WriteFile(cssDest, []byte(getUserCSS(themeFolder)), 0700); err != nil {
+ 		utils.Fatal(err)