Ruby: specify UTF-8 encoding for file IO

server.rb

@@ -19,7 +19,7 @@
 server = WEBrick::HTTPServer.new Port: port, DocumentRoot: root
 
 server.mount_proc '/api/comments' do |req, res|
-  comments = JSON.parse(File.read('./comments.json'))
+  comments = JSON.parse(File.read('./comments.json', encoding: 'UTF-8'))
 
   if req.request_method == 'POST'
     # Assume it's well formed
@@ -28,7 +28,11 @@
       comment[key] = value.force_encoding('UTF-8')
     end
     comments << comment
-    File.write('./comments.json', JSON.pretty_generate(comments, indent: '    '))
+    File.write(
+      './comments.json',
+      JSON.pretty_generate(comments, indent: '    '),
+      encoding: 'UTF-8'
+    )
   end
 
   # always return json