feat: cache + paths (#1)

- Added helper function `ExpandUser`
- Added basic cache impmentations for in-memory and file based caches.

Reviewed-on: #1
Co-authored-by: Felipe M. <me@fmartingr.com>
Co-committed-by: Felipe M. <me@fmartingr.com>

paths/user.go

@@ -0,0 +1,20 @@
+package paths
+
+import (
+	"os/user"
+	"path/filepath"
+	"strings"
+)
+
+func ExpandUser(providedPath string) string {
+	var path string = providedPath
+	usr, _ := user.Current()
+	dir := usr.HomeDir
+
+	if providedPath == "~" {
+		path = dir
+	} else if strings.HasPrefix(providedPath, "~/") {
+		path = filepath.Join(dir, providedPath[2:])
+	}
+	return path
+}