After running the install script as mentioned on GitHub, I get the following error
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* Installing mustache *
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rake aborted!
SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed
/Users/carl-erik.kopseng/.vim/janus/ruby/janus/plugins.rb:42:in `download_and_save_file'
/Users/carl-erik.kopseng/.vim/janus/vim/langs/tasks/mustache.rake:2:in `block in <top (required)>'
/Users/carl-erik.kopseng/.vim/janus/ruby/janus/plugins.rb:82:in `block (2 levels) in define_install_plugin_tasks'
Tasks: TOP => install => mustache:install
(See full trace by running task with --trace)
rake aborted!
Command failed with status (1): [rake install...]
/Users/carl-erik.kopseng/.vim/Rakefile:76:in `block in <top (required)>'
Tasks: TOP => default
(See full trace by running task with --trace)
Rake failed.