add readme for each package

README.md

@@ -0,0 +1,33 @@
+# Go Registry
+
+This package provides a simple registry implementation which allows storing arbitrary values in a memory map.
+
+You can also lock specific keys to prevent them being written, even if no value has yet been set. Locked keys cannot be unlocked.
+
+## Example
+
+```go
+package main
+
+import (
+	"fmt"
+
+	"github.com/annybs/go/registry"
+)
+
+func main() {
+	r := registry.New()
+
+	r.Set("some key", "some text")
+	fmt.Println(r.Get("some key"))
+
+	r.Lock("some key")
+	if err := r.Set("some key", "different text"); err != nil {
+		fmt.Println(err)
+	}
+}
+```
+
+## License
+
+See [LICENSE.md](../LICENSE.md)