Introduce rubocop (or sth. similar) to check code for syntax errors, deprecation warnings, etc.
First of: I'm not bound to rubocop, I'm quite sure that there are other tools out there, which might be preferable. Currently, running rubocop on the source reveals interesting stuff, for example:
lib/schleuder/plugins/key_management.rb:82:5: W: private (on line 80) does not make singleton methods private. Use private_class_method or private inside a class << self block instead.
def self.is_armored_key?(material)
^^^
In my opinion, if developing code together, both, the code and the people, do benefit if there are rules in place which both follow. I'm not after following the official ruby style guide up until 100%, and I guess there are more out there than just one, but maybe we could together decide if there are rules which make sense. AFAIK, it's possible to explicitly tell these tools which rules need to be checked, and which are to be ignored.
This is of course an investment up front, but I think it pays back quite soon. Any opinions regarding this?