schleuder fails to parse message without a subject
If a mail does not have a subject mail.subject
is nil and schleuder is supposed to add a prefix it fails on trying to match it:
undefined method `include?' for nil:NilClass
/opt/schleuder/lib/schleuder/mail/message.rb:404:in `_add_subject_prefix'
/opt/schleuder/lib/schleuder/mail/message.rb:215:in `add_subject_prefix!'
/opt/schleuder/lib/schleuder/runner.rb:48:in `run'
/opt/schleuder/lib/schleuder/cli.rb:35:in `work'
/opt/schleuder/bundler/ruby/2.3.0/gems/thor-0.19.4/lib/thor/command.rb:27:in `run'
/opt/schleuder/bundler/ruby/2.3.0/gems/thor-0.19.4/lib/thor/invocation.rb:126:in `invoke_command'
/opt/schleuder/bundler/ruby/2.3.0/gems/thor-0.19.4/lib/thor.rb:369:in `dispatch'
/opt/schleuder/bundler/ruby/2.3.0/gems/thor-0.19.4/lib/thor/base.rb:444:in `start'
/opt/schleuder/bin/schleuder:12:in `<top (required)>'
/opt/schleuder/bundler/ruby/2.3.0/bin/schleuder:23:in `load'
/opt/schleuder/bundler/ruby/2.3.0/bin/schleuder:23:in `<main>'