Remove references to Follower.user_id.

dashboard/app/controllers/admin_search_controller.rb

@@ -31,7 +31,7 @@ def find_students
         end
         if teachers.first
           array_of_student_ids = Follower.
-            where(user_id: teachers.first[:id]).pluck('student_user_id').to_a
+            where(user: teachers.first).pluck('student_user_id').to_a
           users = users.where(id: array_of_student_ids)
         end
       end

dashboard/app/controllers/transfers_controller.rb

@@ -80,7 +80,7 @@ def create
         follower_same_user_teacher.update_attributes!(section_id: new_section.id)
       else
         unless student.followeds.exists?(section_id: new_section.id)
-          student.followeds.create!(user_id: new_section.user_id, section: new_section)
+          student.followeds.create!(user: new_section.user, section: new_section)
         end
 
         unless stay_enrolled_in_current_section

dashboard/app/models/follower.rb

@@ -32,7 +32,7 @@ def cannot_follow_yourself
   end
 
   def teacher_must_be_teacher
-    errors.add(:user_id, "must be a teacher") unless user.user_type == User::TYPE_TEACHER
+    errors.add(:user, "must be a teacher") unless user.user_type == User::TYPE_TEACHER
   end
 
   validate :cannot_follow_yourself, :teacher_must_be_teacher

dashboard/app/models/user.rb

@@ -729,7 +729,7 @@ def student_of_authorized_teacher?
   end
 
   def student_of?(teacher)
-    followeds.find_by_user_id(teacher.id).present?
+    teachers.include? teacher
   end
 
   def locale
@@ -1207,7 +1207,7 @@ def can_edit_password?
   end
 
   def section_for_script(script)
-    followeds.collect(&:section).find {|section| section.script_id == script.id}
+    sections_as_student.find {|section| section.script_id == script.id}
   end
 
   # Returns the version of our Terms of Service we consider the user as having
@@ -1218,14 +1218,7 @@ def terms_version
     if teacher?
       return terms_of_service_version
     end
-    # As of August 2016, it may be the case that the `followed` exists but
-    # `followed.user` does not as the result of user deletion. In this case, we
-    # ignore any terms of service versions associated with deleted teacher
-    # accounts.
-    followeds.
-      collect {|followed| followed.user.try(:terms_of_service_version)}.
-      compact.
-      max
+    teachers.map(&:terms_of_service_version).try(:compact).try(:max)
   end
 
   # Returns whether the user has accepted the latest major version of the Terms of Service

dashboard/test/controllers/script_levels_controller_test.rb

@@ -15,7 +15,7 @@ class ScriptLevelsControllerTest < ActionController::TestCase
     @teacher = create :teacher
     @admin = create :admin
     @section = create :section, user_id: @teacher.id
-    Follower.create!(section_id: @section.id, student_user_id: @student.id, user_id: @teacher.id)
+    Follower.create!(section_id: @section.id, student_user_id: @student.id, user: @teacher)
 
     @custom_script = create(:script, name: 'laurel', hideable_stages: true)
     @custom_stage_1 = create(:stage, script: @custom_script, name: 'Laurel Stage 1', absolute_position: 1, relative_position: '1')
@@ -1248,7 +1248,7 @@ def assert_caching_enabled(cache_control_header, max_age, proxy_max_age)
 
   def put_student_in_section(student, teacher, script)
     section = create :section, user_id: teacher.id, script_id: script.id
-    Follower.create!(section_id: section.id, student_user_id: student.id, user_id: teacher.id)
+    Follower.create!(section_id: section.id, student_user_id: student.id, user: teacher)
     section
   end
 

dashboard/test/controllers/transfers_controller_test.rb

@@ -137,7 +137,7 @@ class TransfersControllerTest < ActionController::TestCase
   test "multiple students can be transferred" do
     new_student = create(:student)
     Follower.create!(
-      user_id: @teacher.id,
+      user: @teacher,
       student_user: new_student,
       section: @word_section
     )
@@ -153,7 +153,7 @@ class TransfersControllerTest < ActionController::TestCase
   test "students can be transferred to other teachers if they already belong to a section belonging to the other teacher" do
     already_enrolled_section = create(:section, user: @other_teacher, login_type: 'word')
     Follower.create!(
-      user_id: @other_teacher.id,
+      user: @other_teacher,
       student_user: @word_student,
       section: already_enrolled_section
     )

dashboard/test/models/follower_test.rb

@@ -9,8 +9,8 @@ class FollowerTest < ActiveSupport::TestCase
   test "cannot follow yourself" do
     assert_does_not_create(Follower) do
       follower = Follower.create(
-        user_id: @laurel.id,
-        student_user_id: @laurel.id,
+        user: @laurel,
+        student_user: @laurel,
         section: @laurel_section
       )
       refute follower.valid?

dashboard/test/models/user_test.rb

@@ -1477,7 +1477,7 @@ def create_user_with_username(username)
     teacher = create :teacher
     section = create :section, user_id: teacher.id
 
-    follow = Follower.create!(section_id: section.id, student_user_id: student.id, user_id: teacher.id)
+    follow = Follower.create!(section_id: section.id, student_user_id: student.id, user: teacher)
 
     teacher.reload
     student.reload

pegasus/helper_modules/dashboard.rb

@@ -82,10 +82,11 @@ def select(*keys)
     # @return [Array[Integer]] the subset of other_user_ids that are followeds
     #   of the user encapsulated by this class.
     def get_followed_bys(other_user_ids)
-      Dashboard.db[:followers].
+      Dashboard.db[:sections].
+        join(:followers, section_id: :sections__id).
         join(:users, id: :followers__student_user_id).
+        where(sections__user_id: id).
         where(followers__student_user_id: other_user_ids).
-        where(followers__user_id: id).
         where(users__deleted_at: nil, followers__deleted_at: nil).
         select_map(:followers__student_user_id)
     end
@@ -94,10 +95,11 @@ def get_followed_bys(other_user_ids)
     # @return [Boolean] whether other_user_id is a followed of the user
     #   encapsulated by this class.
     def followed_by?(other_user_id)
-      Dashboard.db[:followers].
+      Dashboard.db[:sections].
+        join(:followers, section_id: :sections__id).
         join(:users, id: :followers__student_user_id).
+        where(sections__user_id: id).
         where(followers__student_user_id: other_user_id).
-        where(followers__user_id: id).
         where(users__deleted_at: nil, followers__deleted_at: nil).
         any?
     end

pegasus/helpers/section_api_helpers.rb

@@ -10,11 +10,12 @@
 class DashboardStudent
   # Returns all users who are followers of the user with ID user_id.
   def self.fetch_user_students(user_id)
-    Dashboard.db[:users].
-      join(:followers, student_user_id: :users__id).
-      join(Sequel.as(:users, :users_students), id: :followers__student_user_id).
-      where(followers__user_id: user_id, followers__deleted_at: nil).
-      where(users_students__deleted_at: nil).
+    Dashboard.db[:sections].
+      join(:followers, section_id: :sections__id).
+      join(:users, id: :followers__student_user_id).
+      where(sections__user_id: user_id).
+      where(followers__deleted_at: nil).
+      where(users__deleted_at: nil).
       select(*fields).
       all
   end
@@ -105,12 +106,12 @@ def self.fetch_if_allowed_array(ids, dashboard_user_id)
   end
 
   def self.update_if_allowed(params, dashboard_user_id)
-    user_to_update = Dashboard.db[:users].
-      where(id: params[:id], deleted_at: nil)
+    user_to_update = Dashboard.db[:users].where(id: params[:id], deleted_at: nil)
     return if user_to_update.empty?
-    return if Dashboard.db[:followers].
-      where(student_user_id: params[:id], user_id: dashboard_user_id).
-      where(deleted_at: nil).
+    return if Dashboard.db[:sections].
+      join(:followers, section_id: :sections__id).
+      where(sections__user_id: dashboard_user_id).
+      where(followers__student_user_id: params[:id], followers__deleted_at: nil).
       empty?
 
     fields = {updated_at: DateTime.now}
@@ -383,9 +384,8 @@ def add_student(student)
     created_at = DateTime.now
     Dashboard.db[:followers].insert(
       {
-        user_id: @row[:teacher_id],
-        student_user_id: student_id,
         section_id: @row[:id],
+        student_user_id: student_id,
         created_at: created_at,
         updated_at: created_at,
       }

pegasus/test/fixtures/fake_dashboard.rb

@@ -85,17 +85,14 @@ module FakeDashboard
   #
   FOLLOWERS = [
     {
-      user_id: TEACHER[:id],
       student_user_id: STUDENT[:id],
       section_id: SECTION_NORMAL[:id]
     },
     {
-      user_id: TEACHER_WITH_DELETED[:id],
       student_user_id: DELETED_STUDENT[:id],
       section_id: SECTION_DELETED_FOLLOWERS[:id]
     },
     {
-      user_id: TEACHER_WITH_DELETED[:id],
       student_user_id: SELF_STUDENT[:id],
       section_id: SECTION_DELETED_FOLLOWERS[:id],
       deleted_at: '2016-01-01 00:01:02'

pegasus/test/test_v2_section_routes.rb

@@ -205,15 +205,15 @@ class V2SectionRoutesTest < Minitest::Test
         Dashboard.db.transaction(rollback: :always) do
           before_timestamp = Dashboard.db[:followers].
             where(
-              user_id: FakeDashboard::TEACHER_WITH_DELETED[:id],
+              section_id: FakeDashboard::SECTION_DELETED_FOLLOWERS[:id],
               student_user_id: FakeDashboard::SELF_STUDENT[:id]
             ).
             select_map(:deleted_at)
           @pegasus.post "/v2/sections/#{FakeDashboard::SECTION_DELETED_FOLLOWERS[:id]}/delete"
           assert_equal 204, @pegasus.last_response.status
           after_timestamp = Dashboard.db[:followers].
             where(
-              user_id: FakeDashboard::TEACHER_WITH_DELETED[:id],
+              section_id: FakeDashboard::SECTION_DELETED_FOLLOWERS[:id],
               student_user_id: FakeDashboard::SELF_STUDENT[:id]
             ).
             select_map(:deleted_at)