Now Sphinx is saying:

Warning, treated as error:
/home/travis/build/bigchaindb/bigchaindb/docs/root/source/assets_ko.md:document isn't included in any toctree

That's because none of the new files are included in any "Table of Contents tree" (toctree). That is, none of the new files are listed in an index.rst file. To fix this problem, you could do the following:

1. Move all the new (Korean) files to a new folder docs/root/source/korean/
2. Create a new index.rst file in that folder (docs/root/source/korean/index.rst) with a structure similar to docs/root/source/index.rst but in Korean. This would replace docs/root/source/index_kor.md, which could then be deleted. Note that index.rst files never include the filename extensions (.md or .rst).
3. Link to the new folder index from docs/root/source/index.rst by adding one line to the toctree section:

   ...
   permissions
   private-data
   Data Models <https://docs.bigchaindb.com/projects/server/en/latest/data-models/index.html>
   korean/index

You could also put that new line (korean/index) near the top of the Table of Contents if you like.

@gamjapark I see you did task 1. in my last comment, but you didn't do task 2. or task 3. yet. That is why the checks are still failing.

If you like, I could just merge this pull request and then do a quick pull request of my own to fix the remaining issues. Let me know.

I have resolved all errors!!! Done!!!! 😄
Is there something more to do?

Codecov Report

Merging #2603 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2603   +/-   ##
=======================================
  Coverage   93.59%   93.59%           
=======================================
  Files          45       45           
  Lines        2684     2684           
=======================================
  Hits         2512     2512           
  Misses        172      172

I am sorry for bothering you, again.
I changed the link because i made korean folder. finish...!

Hi @gamjapark - I am in Berlin, Germany, so the delays are probably just because we're in different time zones. I see you got all the tests passing and everything looks good. I will merge this pull request now.