gistfile1.rb

  # Before
  
  def index
    if current_user.is_student?
      @assignments = current_user.assignments.order(created_at: :desc)
      render "student_index"
    elsif current_user.is_admin?
      @current_student = params[:student]
      @students = User.get_all_students
      @average_grade = 0
      if @current_student.nil? || @current_student.empty?
        @average_grade = Assignment.average_percentage
        @assignments = Assignment.all.order(created_at: :desc)
      else
        @average_grade = User.find(@current_student).current_grade
        @assignments = Assignment.where(user_id: @current_student).order(created_at: :desc)
      end
      render "admin_index"
    end
  end

  # After
  
  # send first conditional to a different controller...

classs AssignmentsController < ApplicationController
  def index
    @assignments = current_user.assignments.order(created_at: :desc)
  end
end

class Admin::AssignmentsController < ApplicationController
  if params[:student]
    student = Student.find(params[:student])
    @average_grade = student.current_grade
    @assignments = student.assignments.order(created_at: :desc)
  else
    @average_grade = Assignment.average_percentage
    @assignments = Assignment.all.order(created_at: :desc)
  end
end