add minitest to development group in Gemfile

[francisluong]

Was getting this:

fx-mbp-13:bluemonk_ipaddress fluong$ rake test
/Users/fluong/.rvm/rubies/ruby-2.2.1/bin/ruby --verbose -w -I"lib:lib:test" -I"/Users/fluong/.rvm/gems/ruby-2.2.1/gems/rake-11.1.0/lib" "/Users/fluong/.rvm/gems/ruby-2.2.1/gems/rake-11.1.0/lib/rake/rake_test_loader.rb" "test/**/*_test.rb" 
/Users/fluong/github/bluemonk_ipaddress/test/test_helper.rb:2:in `require': cannot load such file -- minitest/autorun (LoadError)
        from /Users/fluong/github/bluemonk_ipaddress/test/test_helper.rb:2:in `<top (required)>'
        from /Users/fluong/github/bluemonk_ipaddress/test/ipaddress/ipv4_test.rb:1:in `require'
        from /Users/fluong/github/bluemonk_ipaddress/test/ipaddress/ipv4_test.rb:1:in `<top (required)>'
        from /Users/fluong/.rvm/gems/ruby-2.2.1/gems/rake-11.1.0/lib/rake/rake_test_loader.rb:10:in `require'
        from /Users/fluong/.rvm/gems/ruby-2.2.1/gems/rake-11.1.0/lib/rake/rake_test_loader.rb:10:in `block (2 levels) in <main>'
        from /Users/fluong/.rvm/gems/ruby-2.2.1/gems/rake-11.1.0/lib/rake/rake_test_loader.rb:9:in `each'
        from /Users/fluong/.rvm/gems/ruby-2.2.1/gems/rake-11.1.0/lib/rake/rake_test_loader.rb:9:in `block in <main>'
        from /Users/fluong/.rvm/gems/ruby-2.2.1/gems/rake-11.1.0/lib/rake/rake_test_loader.rb:4:in `select'
        from /Users/fluong/.rvm/gems/ruby-2.2.1/gems/rake-11.1.0/lib/rake/rake_test_loader.rb:4:in `<main>'
rake aborted!
Command failed with status (1): [ruby --verbose -w -I"lib:lib:test" -I"/Users/fluong/.rvm/gems/ruby-2.2.1/gems/rake-11.1.0/lib" "/Users/fluong/.rvm/gems/ruby-2.2.1/gems/rake-11.1.0/lib/rake/rake_test_loader.rb" "test/**/*_test.rb" ]
/Users/fluong/.rvm/gems/ruby-2.2.1/bin/ruby_executable_hooks:15:in `eval'
/Users/fluong/.rvm/gems/ruby-2.2.1/bin/ruby_executable_hooks:15:in `<main>'
Tasks: TOP => test
(See full trace by running task with --trace)

But now it works.

[francisluong]

fx-mbp-13:bluemonk_ipaddress fluong$ rake test
/Users/fluong/.rvm/rubies/ruby-2.2.1/bin/ruby --verbose -w -I"lib:lib:test" -I"/Users/fluong/.rvm/gems/ruby-2.2.1/gems/rake-11.1.0/lib" "/Users/fluong/.rvm/gems/ruby-2.2.1/gems/rake-11.1.0/lib/rake/rake_test_loader.rb" "test/**/*_test.rb" 
/Users/fluong/github/bluemonk_ipaddress/lib/ipaddress.rb:72: warning: mismatched indentations at 'end' with 'unless' at 70
/Users/fluong/github/bluemonk_ipaddress/lib/ipaddress/prefix.rb:81: warning: mismatched indentations at 'end' with 'class' at 21
/Users/fluong/github/bluemonk_ipaddress/test/ipaddress/ipv6_test.rb:18: warning: duplicated key at line 30 ignored: "1080:0:0:0:8:800:200C:417A"
/Users/fluong/github/bluemonk_ipaddress/test/ipaddress/ipv6_test.rb:18: warning: unused literal ignored
/Users/fluong/github/bluemonk_ipaddress/test/ipaddress/ipv6_test.rb:20: warning: duplicated key at line 31 ignored: "1080::8:800:200C:417A"
/Users/fluong/github/bluemonk_ipaddress/test/ipaddress/ipv6_test.rb:20: warning: unused literal ignored
Run options: --seed 33632

# Running:

......................................................................................................................

Finished in 0.477777s, 246.9769 runs/s, 1052.7914 assertions/s.

118 runs, 503 assertions, 0 failures, 0 errors, 0 skips