Add GitHub edit link

book.json

@@ -1,16 +1,21 @@
 {
-	"plugins": [
-		"insert-logo-link"
-	],
-	"pluginsConfig": {
-		"insert-logo-link": {
-			"src": "images/logo.png",
-			"url": "https://vcvrack.com/"
-		}
-	},
-	"structure": {
-		"readme": "Introduction.md",
-		"summary": "TOC.md",
-		"glossary": "Glossary.md"
-	}
+  "plugins": [
+    "insert-logo-link",
+    "github-edit"
+  ],
+  "pluginsConfig": {
+    "insert-logo-link": {
+      "src": "images/logo.png",
+      "url": "https://vcvrack.com/"
+    },
+    "github-edit": {
+      "repo": "VCVRack/manual",
+      "branch": "master"
+    }
+  },
+  "structure": {
+    "readme": "Introduction.md",
+    "summary": "TOC.md",
+    "glossary": "Glossary.md"
+  }
 }