upgrade rails version and fix bug

app/models/forem/concerns/viewable.rb

@@ -16,7 +16,7 @@ def view_for(user)
       # Track when users last viewed topics
       def register_view_by(user)
         return unless user
-        view = views.find_or_create_by(user_id: user.id)
+        view = View.find_or_create_by(user: user, viewable: self)
         view.increment!('count')
         increment!(:views_count)
 

app/models/forem/subscription.rb

@@ -9,7 +9,7 @@ def send_notification(post_id)
       # If a user cannot be found, then no-op
       # This will happen if the user record has been deleted.
       if subscriber.present?
-        SubscriptionMailer.topic_reply(post_id, subscriber.id).deliver
+        SubscriptionMailer.topic_reply(post_id, subscriber.id).deliver_now
       end
     end
   end

db/migrate/20110221092741_create_forem_topics.rb

@@ -5,7 +5,7 @@ def change
       t.integer :user_id
       t.string :subject
 
-      t.timestamps
+      t.timestamps :null => false
     end
   end
 end

db/migrate/20110221094502_create_forem_posts.rb

@@ -5,7 +5,7 @@ def change
       t.text :text
       t.integer :user_id
 
-      t.timestamps
+      t.timestamps :null => false
     end
   end
 end

db/migrate/20111103210835_create_forem_categories.rb

@@ -2,7 +2,7 @@ class CreateForemCategories < ActiveRecord::Migration
   def change
     create_table :forem_categories do |t|
       t.string :name, :null => false
-      t.timestamps
+      t.timestamps :null => false
     end
   end
 end

forem.gemspec

@@ -22,7 +22,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'sass-rails', '~> 4.0'
   s.add_development_dependency 'coffee-rails', '~> 4.0'
 
-  s.add_dependency 'rails', '~> 4.0', '<= 4.2'
+  s.add_dependency 'rails', '~> 4.0', '<= 4.2.3'
   s.add_dependency 'simple_form', '~> 3.0'
   s.add_dependency 'sanitize', '2.0.6'
   s.add_dependency 'workflow', '1.0.0'