update README

Author: myfreess

README.mbt.md

@@ -1 +1,31 @@
-# jsondiff
+# jsondiff
+
+Simple Json Structrual Diff Library
+
+```mbt test
+let old : Json = {
+    "foo": [1, 2, 3],
+    "bar": { "baz": "qux" }
+}
+
+let new : Json = {
+    "foo": [1, 2, 4],
+    "bar": { "baz": "quux" },
+    "new_key": true
+}
+inspect(JsonDiff::diff_string(old, new).unwrap(), content=(
+  #| {
+  #|+  new_key: true
+  #|   foo: [
+  #|     1
+  #|     2
+  #|-    3
+  #|+    4
+  #|   ]
+  #|   bar: {
+  #|-    baz: "qux"
+  #|+    baz: "quux"
+  #|   }
+  #| }
+))
+```

stringify.mbt

@@ -94,15 +94,7 @@ let output_colorful_text_for_terminal : Ref[Bool] = Ref::new(false)
 fn Array::push_line(self : Array[String], tag : String, line : String) -> Unit {
   let tagged_line = "\{tag}\{line}"
   if output_colorful_text_for_terminal.val {
-    match tag {
-      "+" =>
-        // green
-        self.push("\u{1b}[32m\{tag}\{line}\u{1b}[0m")
-      "-" =>
-        // red
-        self.push("\u{1b}[31m\{tag}\{line}\u{1b}[0m")
-      _ => self.push(tagged_line)
-    }
+    ...
   } else {
     self.push(tagged_line)
   }