Update README.md

README.md

@@ -1,2 +1,65 @@
 # go-mp4tag
 MP4 tagger written in Go.
+
+## Setup
+```
+go get github.com/Sorrow446/go-mp4tag
+```
+```go
+import "github.com/Sorrow446/go-mp4tag"
+```
+
+## Usage Examples
+```go
+	tags := &mp4tag.Tags{
+		Album: "album",
+		AlbumArtist: "album artist",
+		Title:       "title",
+		TrackNumber: 1,
+		TrackTotal:  20,
+		Genre: "genre",
+		DiskNumber:  3,
+		DiskTotal:   10,
+		Comment:     "comment",
+	}
+	err := mp4tag.Write("1.m4a", tags)
+	if err != nil {
+		panic(err)
+	}
+```
+ Write album, album artist, title, track number, track total, genre, disk number, disk total, and comment tags.
+ 
+ 
+ ```go
+	tags := &mp4tag.Tags{
+		Custom: map[string]string{
+			"CUSTOMFIELD": "custom field",
+			"CUSTOMFIELD2": "custom field 2",
+		},
+		Delete: []string{"genre", "cover"},
+	}
+	err := mp4tag.Write("1.m4a", tags)
+	if err != nil {
+		panic(err)
+	}
+```
+Write two custom fields named `CUSTOMFIELD` and `CUSTOMFIELD2`, delete genre tag, and remove cover.
+
+
+```go
+	coverBytes, err := ioutil.ReadFile("cover.jpg")
+	if err != nil {
+		panic(err)
+	}
+	tags := &mp4tag.Tags{
+		Cover: coverBytes,
+	}
+	err = mp4tag.Write("1.m4a", tags)
+	if err != nil {
+		panic(err)
+	}
+```
+Write cover from `cover.jpg`.
+
+## Thank you
+This library relies heavily on abema's go-mp4 library.