gem: add rubocop and fix style

lib/openvpn-status-web/int_patch.rb

@@ -1,16 +1,16 @@
 
 class Integer
   def as_bytes
-    return "1 Byte" if self == 1
-    
-    label = ["Bytes", "KiB", "MiB", "GiB", "TiB"]
+    return '1 Byte' if self == 1
+
+    label = %w[Bytes KiB MiB GiB TiB]
     i = 0
-    num = self.to_f
-    while num >= 1024 do
-      num = num / 1024
+    num = to_f
+    while num >= 1024
+      num /= 1024
       i += 1
     end
-    
+
     "#{format('%.2f', num)} #{label[i]}"
   end
 end