Rails Byebug permission Errno::EACCES error @ rb_sysopen - /.byebug_history

I've read several similar topics where it is suggested to check/change permissions. And I already did this but it doesn't work.

Here is my project folder permissions:

$ stat trains
File: ‘trains’
Size: 4096          Blocks: 8          IO Block: 4096   directory
Device: 816h/2070d  Inode: 265254      Links: 14
Access: (0777/drwxrwxrwx)  Uid: ( 1000/   xxx)   Gid: ( 1000/   xxx)
Access: 2016-07-19 08:24:43.633340992 +0300
Modify: 2016-07-19 08:20:59.785332645 +0300
Change: 2016-07-19 08:24:43.533340989 +0300
Birth: -

Last lines from my terminal log:

Ero::EACCES - Permission denied @ rb_sysopen - /.byebug_history: byebug (9.0.5) lib/byebug/history.rb:39:in save' byebug (9.0.5) lib/byebug/interface.rb:110:inautosave' byebug (9.0.5) lib/byebug/processors/command_processor.rb:121:in after_repl' byebug (9.0.5) lib/byebug/processors/command_processor.rb:100:inprocess_commands' byebug (9.0.5) lib/byebug/processors/command_processor.rb:56:in at_line' byebug (9.0.5) lib/byebug/context.rb:96:inat_line' app/controllers/stations_controller.rb:13:in `new'

I tried to create /.byebug_history file myself with 777 permissions but it didn't help.

I have checked that error comes from .rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/byebug-9.0.5/lib/byebug/history.rb

from this part (if I comment it error disappears)

  open(Setting[:histfile], 'w') do |file|
    n_cmds.times { file.puts(pop) }
  end

But I have no idea why is it happening.

I have already checked my other projects and created a new one from scratch and all of them throw the same error if I try to use byebug.