title: Rails NoMethodError when calling a model method from a controller
body: <p>I want to call a method from my controller and am receiving a NoMethodError: undefined method `combine_table_lines' for Data:Class</p>
  
  <p>I am new to rails, so I apologize if this is something very basic.</p>
  
  <p>Controller: data_controller.rb</p>
  
  <pre><code>class DataController &lt; ApplicationController
  
    def abetReport
       @slos = Answer.joins(knowledge_topic: :student_learning_outcomes).select( 
               'student_learning_outcomes.title', :is_correct, "count(answers.id) AS  
                total_answers").group('student_learning_outcomes.id', :is_correct)
       @slos_combined = Data.combine_table_lines(@slos) 
  
  
    end
  end
  </code></pre>
  
  <p>Model: data.rb</p>
  
  <pre><code>class Data
  
    def self.combine_table_lines(data)
       #body of method 
    end # end method
  
  end
  </code></pre>
  
  <p>Thank you in advance for any help.</p>