1. Created blank repository for new blog website using Middleman, Github Pages, and the middleman-gh-pages gem.
2. Tried to upload my blog for the first time using the following sequence of commands and received the following error:

 (master)$ git init
 (master)$ git add . 
 (master)$ git commit -m "Initial commit; first blog post" 
 (master)$ remote add origin git@github.com:wakproductions/blog.git 
 (master)$ rake publish  
cd /Users/wkotzan/Development/wakproductions-tech-blog
cd -
cd /Users/wkotzan/Development/wakproductions-tech-blog/build
git init
Initialized empty Git repository in /Users/wkotzan/Development/wakproductions-tech-blog/build/.git/
git remote add origin git@github.com:wakproductions/blog.git
git fetch --depth 1 origin gh-pages
fatal: Couldn't find remote ref gh-pages
rake aborted!
Command failed with status (128): [git fetch --depth 1 origin gh-pages...]
/Users/wkotzan/.rvm/gems/ruby-2.3.0/gems/middleman-gh-pages-0.3.0/lib/middleman-gh-pages/tasks/gh-pages.rake:42:in `block (2 levels) in <top (required)>'
/Users/wkotzan/.rvm/gems/ruby-2.3.0/gems/middleman-gh-pages-0.3.0/lib/middleman-gh-pages/tasks/gh-pages.rake:39:in `block in <top (required)>'
/Users/wkotzan/.rvm/gems/ruby-2.3.0/gems/rake-11.2.2/exe/rake:27:in `<top (required)>'
/Users/wkotzan/.rvm/gems/ruby-2.3.0/bin/ruby_executable_hooks:15:in `eval'
/Users/wkotzan/.rvm/gems/ruby-2.3.0/bin/ruby_executable_hooks:15:in `<main>'
Tasks: TOP => publish => sync_build_dir => prepare_build_dir => /Users/wkotzan/Development/wakproductions-tech-blog/build/.git/refs/remotes/origin/gh-pages
(See full trace by running task with --trace) 

This error occurs because you need to have the gh-pages branch existing already. Fixed the error by creating the branch:

 (master)$ git checkout -b gh-pages
Switched to a new branch 'gh-pages'
 (gh-pages)$ git checkout master
Switched to branch 'master'
 (master)$ rake publish

The publish operation then worked.

I later ran into the following error:

 (master)$ rake publish
cd /Users/wkotzan/Development/wakproductions-tech-blog/build
git fetch --depth 1 origin gh-pages
remote: Total 0 (delta 0), reused 0 (delta 0), pack-reused 0
From github.com:wakproductions/blog
 * branch            gh-pages   -> FETCH_HEAD
git reset --hard origin/gh-pages
HEAD is now at b0a5c51 Site updated to 5026e1c
cd -
mv /Users/wkotzan/Development/wakproductions-tech-blog/build/.git /var/folders/j0/16g0mm8506n123wd4pwt8nmc0000gn/T/d20170113-33919-upb9fz
cd /Users/wkotzan/Development/wakproductions-tech-blog
bundle exec middleman build --clean
== Blog Sources: {year}-{month}-{day}-{title}.html (:prefix + :sources)

   ...omitted...

Project built successfully.
cd -
mv /var/folders/j0/16g0mm8506n123wd4pwt8nmc0000gn/T/d20170113-33919-upb9fz/.git /Users/wkotzan/Development/wakproductions-tech-blog/build
cd /Users/wkotzan/Development/wakproductions-tech-blog
cd -
cd /Users/wkotzan/Development/wakproductions-tech-blog/build
git add --all
git commit -m "Site updated to 61dbbd5"
[master 3b55444] Site updated to 61dbbd5
 14 files changed, 276 insertions(+), 51 deletions(-)
 create mode 100644 2017/01/12.html
 create mode 100644 2017/01/12/s3-code-examples.html
git push origin gh-pages
error: src refspec gh-pages does not match any.
error: failed to push some refs to 'git@github.com:wakproductions/blog.git'
rake aborted!
Command failed with status (1): [git push origin gh-pages...]
/Users/wkotzan/.rvm/gems/ruby-2.3.1/gems/middleman-gh-pages-0.3.1/lib/middleman-gh-pages/tasks/gh-pages.rake:101:in `block (2 levels) in <top (required)>'
/Users/wkotzan/.rvm/gems/ruby-2.3.1/gems/middleman-gh-pages-0.3.1/lib/middleman-gh-pages/tasks/gh-pages.rake:94:in `block in <top (required)>'
/Users/wkotzan/.rvm/gems/ruby-2.3.1/gems/rake-11.2.2/exe/rake:27:in `<top (required)>'
/Users/wkotzan/.rvm/gems/ruby-2.3.1/bin/ruby_executable_hooks:15:in `eval'
/Users/wkotzan/.rvm/gems/ruby-2.3.1/bin/ruby_executable_hooks:15:in `<main>'
Tasks: TOP => publish
(See full trace by running task with --trace)

This problem error: src refspec gh-pages does not match any. was resolved by deleting the build directory and trying rake publish again.