Remove some calls to all. They are not required, and Rails4 raises warnings about them.

app/controllers/admin/email_controller.rb

@@ -16,7 +16,7 @@ class Admin::EmailController < Admin::AdminController
   end
 
   def logs
-    @email_logs = EmailLog.limit(50).includes(:user).order('created_at desc').all
+    @email_logs = EmailLog.limit(50).includes(:user).order('created_at desc').to_a
     render_serialized(@email_logs, EmailLogSerializer)
   end
 

app/controllers/admin/groups_controller.rb

@@ -1,6 +1,6 @@
 class Admin::GroupsController < Admin::AdminController
   def index
-    groups = Group.order(:name).all
+    groups = Group.order(:name).to_a
     render_serialized(groups, BasicGroupSerializer)
   end
 

app/controllers/notifications_controller.rb

@@ -3,7 +3,7 @@ class NotificationsController < ApplicationController
   before_filter :ensure_logged_in
 
   def index
-    notifications = current_user.notifications.recent.includes(:topic).all.to_a
+    notifications = current_user.notifications.recent.includes(:topic)
 
     if notifications.present?
       notifications += current_user.notifications
@@ -11,9 +11,9 @@ class NotificationsController < ApplicationController
         .where(read: false, notification_type: Notification.types[:private_message])
         .where('id < ?', notifications.last.id)
         .limit(5)
-        .to_a
     end
 
+    notifications = notifications.to_a
     current_user.saw_notification_id(notifications.first.id) if notifications.present?
     current_user.reload
     current_user.publish_notifications_state

app/controllers/post_actions_controller.rb

@@ -31,7 +31,7 @@ class PostActionsController < ApplicationController
     users = User.select(['null as post_url','users.id', 'users.username', 'users.username_lower', 'users.email','post_actions.related_post_id'])
                 .joins(:post_actions)
                 .where(['post_actions.post_id = ? and post_actions.post_action_type_id = ? and post_actions.deleted_at IS NULL', @post.id, @post_action_type_id])
-                .all
+                .to_a
 
     urls = Post.urls(users.map{|u| u.related_post_id})
     users.each do |u|