my github master branch no code when I run the following code

[zdrjson]

➜ octopress git:(source) ✗ rake generate

Generating Site with Jekyll

➜ octopress git:(source) ✗ rake preview
Starting to watch source with Jekyll and Compass. Starting Rack on port 4000
rake aborted!
Errno::ENOENT: No such file or directory - jekyll
/Users/json/Desktop/octopress/Rakefile:84:in spawn' /Users/json/Desktop/octopress/Rakefile:84:inblock in <top (required)>'
Tasks: TOP => preview
(See full trace by running task with --trace)
➜ octopress git:(source) ✗ rake deploy

Deploying branch to Github Pages

Pulling any updates from Github Pages

cd _deploy
There is no tracking information for the current branch.
Please specify which branch you want to merge with.
See git-pull(1) for details.

git pull <remote> <branch>

If you wish to set tracking information for this branch you can do so with:

git branch --set-upstream-to=origin/<branch> master

cd -
rm -rf _deploy/index.html

Copying public to _deploy

cp -r public/. _deploy
cd _deploy

Committing: Site updated at 2016-05-28 13:45:18 UTC

[master 75b38fa] Site updated at 2016-05-28 13:45:18 UTC
1 file changed, 1 deletion(-)
delete mode 100644 index.html

Pushing generated _deploy website

Counting objects: 5, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (2/2), done.
Writing objects: 100% (5/5), 467 bytes | 0 bytes/s, done.
Total 5 (delta 0), reused 0 (delta 0)
To https://github.com/zdrjson/zdrjson.github.io

• [new branch] master -> master

Github Pages deploy complete

cd -