[ADD] microbit.js in ruby-to-blocks-converter and change index.js

Author: rikutons

src/lib/ruby-to-blocks-converter/index.js

@@ -37,6 +37,7 @@ class RubyToBlocksConverter {
             OperatorsConverter,
             VariablesConverter,
             MyBlocksConverter,
+            MicroBitConverter,
 			MusicConverter,
             EV3Converter,
             Wedo2Converter

src/lib/ruby-to-blocks-converter/microbit.js

@@ -0,0 +1,10 @@
+/* global Opal */
+import _ from 'lodash';
+
+/**
+ * Music converter
+ */
+const MicroBitConverter = {
+};
+
+export default MicroBitConverter;