pre-commit.rb

#!/usr/bin/env bash

###############################################################
# Prevents a commit when Gemfile has references to local gems #
###############################################################

if 
    test "$(git diff-index --cached HEAD -G'\Wpath(:|\s?=\>)' -- Gemfile)"
then
    echo "Error: you have references to local gems in your Gemfile. Commit aborted."
    exit 1
fi

I had this as mine already (stolen from some blog post some where on the internet):

$ #!/usr/bin/env ruby
$ # A pre-commit hook script to ensure that no local gem dependencies (gem 'asdf', path: '~/local')
$ # exist in your Gemfile before commiting.`
$ # Allows gems to be loaded from source within the current project, but not from outside.

$ puts 'Checking for local dependencies in your Gemfile.'
$ ROOT_PATH = File.expand_path('../../..', FILE)
$ NESTED_GEMSPECS = Dir["#{ROOT_PATH}/*/.gemspec"]
$ GEMFILE = ENV['BUNDLE_GEMFILE'] || File.join(ROOT_PATH, 'Gemfile')

$ def local?(gemspec)
$ gemspec.source.instance_of?(Bundler::Source::Path)
$ end
$ def nested?(gemspec)
$ NESTED_GEMSPECS.any? { |filename| filename.include?(gemspec.name) }
$ end

$ if open(GEMFILE) { |gemfile| gemfile.grep(/path/) }
$ require 'rubygems'
$ require 'bundler/setup'
$ local_gems = Gem.loaded_specs.values.select do |gemspec|
$ local?(gemspec) and not nested?(gemspec)
$ end
$ unless local_gems.empty? then raise SyntaxError,
$ "You have local dependencies in your Gemfile:"
$ " #{local_gems.map{|g| g.name + ' is loading from ' + g.source.path.to_s}.join(', ')}."
$ " Remove the :path parameter from this/these gems in your Gemfile before committing." end
$ end