Add Meta field to Attachment

mastodon.go

@@ -232,6 +232,21 @@ type Attachment struct {
 	PreviewURL  string         `json:"preview_url"`
 	TextURL     string         `json:"text_url"`
 	Description string         `json:"description"`
+	Meta        AttachmentMeta `json:"meta"`
+}
+
+// AttachmentMeta holds information for attachment metadata.
+type AttachmentMeta struct {
+	Original Size `json:"original"`
+	Small    Size `json:"small"`
+}
+
+// Size holds information for attatchment size.
+type Size struct {
+	Width  int64   `json:"width"`
+	Height int64   `json:"height"`
+	Size   string  `json:"size"`
+	Aspect float64 `json:"aspect"`
 }
 
 // Emoji hold information for CustomEmoji.