couldn't get rake commands to work

[goodwordalchemy]

I'm using OS X mavericks. I copied and pastded gemfile into a file called Gemfile in my Jekyll Blog's directory. Here's the stack trace from trying to make a new post:

david-goldbergs-MacBook-Pro:goodwordalchemy.github.io davidgoldberg$ rake post["30 days goals"] --trace
** Invoke post (first_time)
** Execute post
rake aborted!
undefined method `[]' for nil:NilClass
/Users/davidgoldberg/Code/goodwordalchemy.github.io/rakefile:87:in `block in <top (required)>'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rake/task.rb:228:in `call'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rake/task.rb:228:in `block in execute'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rake/task.rb:223:in `each'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rake/task.rb:223:in `execute'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rake/task.rb:166:in `block in invoke_with_call_chain'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/monitor.rb:211:in `mon_synchronize'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rake/task.rb:159:in `invoke_with_call_chain'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rake/task.rb:152:in `invoke'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rake/application.rb:143:in `invoke_task'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rake/application.rb:101:in `block (2 levels) in top_level'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rake/application.rb:101:in `each'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rake/application.rb:101:in `block in top_level'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rake/application.rb:110:in `run_with_threads'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rake/application.rb:95:in `top_level'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rake/application.rb:73:in `block in run'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rake/application.rb:160:in `standard_exception_handling'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rake/application.rb:70:in `run'
/usr/bin/rake:37:in `<main>'
Tasks: TOP => post
david-goldbergs-MacBook-Pro:goodwordalchemy.github.io davidgoldberg$