Add detailed README documentation with examples.

Expand the README to include license information, badges, and detailed documentation. Also provide example usage of the `niljson` package to help users understand how to integrate and use nullable JSON fields in their Go applications.

README.md

@@ -1,2 +1,80 @@
-# niljson
+<!--
-A simple Go package for unmarshalling null-able JSON types
+SPDX-FileCopyrightText: 2024 Winni Neessen <wn@neessen.dev>
+
+SPDX-License-Identifier: CC0-1.0
+-->
+
+# niljson - A simple Go package for unmarshalling null-able JSON types
+
+[![GoDoc](https://godoc.org/github.com/wneessen/niljson?status.svg)](https://pkg.go.dev/github.com/wneessen/niljson)
+[![codecov](https://codecov.io/gh/wneessen/niljson/branch/main/graph/badge.svg?token=W4QI1RMR4L)](https://codecov.io/gh/wneessen/niljson)
+[![Go Report Card](https://goreportcard.com/badge/github.com/wneessen/niljson)](https://goreportcard.com/report/github.com/wneessen/niljson)
+[![REUSE status](https://api.reuse.software/badge/github.com/wneessen/niljson)](https://api.reuse.software/info/github.com/wneessen/niljson)
+<a href="https://ko-fi.com/D1D24V9IX"><img src="https://uploads-ssl.webflow.com/5c14e387dab576fe667689cf/5cbed8a4ae2b88347c06c923_BuyMeACoffee_blue.png" height="20" alt="buy ma a coffee"></a>
+
+niljson provides a simple and efficient way to handle nullable JSON fields during the unmarshalling process. 
+In JSON, it's common to encounter fields that can be `null`, but handling these fields in Go can be cumbersome, 
+especially when dealing with primitive types like `int`, `float64`, `bool`. These types can all be either `0` (as value)
+or `null`. In Go you can always work with pointers but these, of course, can lead to unhandled nil pointer dereferences.
+
+**niljaon** addresses this challenge by offering a set of types that can seamlessly handle `null` values during 
+unmarshalling, allowing your Go applications to work with JSON data more naturally and with fewer boilerplate 
+checks for `nil` values.
+
+### Key Features
+
+- **Nullable Types**: Provides a range of nullable types (`NilString`, `NilInt`, `NilFloat`, `NilBool`, etc.) that 
+  are easy to use and integrate into your existing Go structs.
+- **Seamless Integration**: These types work just like Go's standard types but add support for `null` values, 
+  enabling cleaner and more maintainable code.
+- **JSON Unmarshalling Support**: Automatically handles the unmarshalling of JSON fields, converting `null` JSON 
+  values to Go's `nil` or zero values, depending on the context.
+- **Minimalistic and Lightweight**: Designed to be lightweight and unobtrusive, so it won't bloat your application 
+  or introduce unnecessary dependencies (only relies on the Go standard library)
+
+### Example Usage
+
+```go
+package main
+
+import (
+    "encoding/json"
+    "fmt"
+    "os"
+    
+    "github.com/wneessen/niljson"
+)
+
+type JSONType struct {
+    Bool       niljson.NilBoolean `json:"bool"`
+	Float32    niljson.NilFloat32 `json:"float32,omitempty"`
+    Float64    niljson.NilFloat64 `json:"float64"`
+    Int        niljson.NilInt     `json:"int"`
+    Int64      niljson.NilInt64   `json:"int64"`
+    NullString niljson.NilString  `json:"nil"`
+    String     niljson.NilString  `json:"string"`
+}
+
+func main() {
+    data := []byte(`{"string":"test", "int":123, "int64": 12345678901234, "float64":0, "nil":null, "bool":true}`)
+    
+    var example JSONType
+    if err := json.Unmarshal(data, &example); err != nil {
+        fmt.Println("failed to unmarshal JSON:", err)
+        os.Exit(1)
+    }
+
+    if example.Bool.NotNil() {
+        fmt.Printf("Bool is: %t\n", example.Bool.Value())
+    }
+	if example.Float64.IsNil() {
+		fmt.Println("Float 32 is NIL")
+	}
+	if example.Float64.NotNil() {
+		fmt.Printf("Float is: %f\n", example.Float64.Value())
+	}
+    if !example.String.IsNil() {
+        fmt.Printf("String is: %s\n", example.String.Value())
+    }
+}
+```