Ruby object that returns all declared associations in your Rails models when given the filepath to your Rails app

fetch_model_associations.rb

class Associator
     attr_reader :rails_app_dir, :associations
 
     ASSOCIATION_TYPES = [
         "belongs_to",
         "has_one",
         "has_many",
         "has_and_belongs_to_many"
     ]
 
     def initialize(rails_app_dir)
         @rails_app_dir = rails_app_dir
         @associations = fetch_associations
     end
 
     def renew
         return Associator.new(@rails_app_dir)
     end
 
 
 private ###########################################
     def fetch_models_list
         return Dir.open(@rails_app_dir.gsub(/\/$/, "") + "/app/models").entries.select {|entry| entry.match(/.rb$/)}
     end
 
     def fetch_associations
         payload = {}
         models_list = fetch_models_list
         unless models_list.empty?
             models_list.each do |filename|
                 filepath = @rails_app_dir + "/app/models/" + filename
                 payload[filename.gsub(/.rb$/, '')] = File.readlines(filepath).select {|line| line =~ Regexp.new(ASSOCIATION_TYPES.join("#{/\b/}|"))}
             end
             payload.each {|filename, associations|
                 associations.map! {|association| association.strip}
                 payload[filename] = associations.group_by {|e| e.match(Regexp.new ASSOCIATION_TYPES.join("#{/\b/}|"))[0]}
             }
             pp payload
             return payload
         else
             return false
         end
     end
 ###################################################
 end

Put this file wherever and import into your console. Instantiate with your desired Rails (absolute) app path and you're off to the races!