diff --git a/CHANGELOG.md b/CHANGELOG.md
index f09380ad8..b18cab9aa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@
 - Notify an user if the available disk space reaches a configured threshold
 - Invoices generated outside of production environment will be watermarked
 - Keep track of currently logged user on each generated invoice
+- Fix a bug: unable to add a file attachment to an event
 - Fix a security issue: updated to devise 4.6.0 to fix [CVE-2019-5421](https://github.com/plataformatec/devise/issues/4981)
 - Fix a security issue: updated Rails to 4.2.11.1 to fix [CVE-2019-5418](https://groups.google.com/forum/#!topic/rubyonrails-security/pFRKI96Sm8Q) and [CVE-2019-5419](https://groups.google.com/forum/#!topic/rubyonrails-security/GN7w9fFAQeI)
 - Removed deprecated Capistrano deployment system
diff --git a/app/controllers/api/events_controller.rb b/app/controllers/api/events_controller.rb
index 127b8fa5d..0791b8de0 100644
--- a/app/controllers/api/events_controller.rb
+++ b/app/controllers/api/events_controller.rb
@@ -96,7 +96,7 @@ class API::EventsController < API::ApiController
                                                      :recurrence_end_at, :category_id, :event_theme_ids, :age_range_id,
                                                      event_theme_ids: [],
                                                      event_image_attributes: [:attachment],
-                                                     event_files_attributes: %i[id attachment_destroy],
+                                                     event_files_attributes: %i[id attachment _destroy],
                                                      event_price_categories_attributes: %i[id price_category_id amount _destroy])
     EventService.process_params(event_preparams)
   end
diff --git a/app/models/event_file.rb b/app/models/event_file.rb
index fb6c7e469..34d788366 100644
--- a/app/models/event_file.rb
+++ b/app/models/event_file.rb
@@ -1,5 +1,8 @@
+# frozen_string_literal: true
+
+# Event PDF attachements
 class EventFile < Asset
-  mount_uploader :attachment, ProjectCaoUploader
+  mount_uploader :attachment, EventFileUploader
 
   validates :attachment, file_size: { maximum: 20.megabytes.to_i }
 end
diff --git a/app/uploaders/event_file_uploader.rb b/app/uploaders/event_file_uploader.rb
new file mode 100644
index 000000000..d794464e1
--- /dev/null
+++ b/app/uploaders/event_file_uploader.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+# CarrierWave uploader for event attachments
+class EventFileUploader < CarrierWave::Uploader::Base
+  # Include RMagick or MiniMagick support:
+  # include CarrierWave::RMagick
+  # include CarrierWave::MiniMagick
+  include UploadHelper
+
+  # Choose what kind of storage to use for this uploader:
+  storage :file
+  after :remove, :delete_empty_dirs
+  # storage :fog
+
+  # Override the directory where uploaded files will be stored.
+  # This is a sensible default for uploaders that are meant to be mounted:
+  def store_dir
+    "#{base_store_dir}/#{model.id}"
+  end
+
+  def base_store_dir
+    "uploads/#{model.class.to_s.underscore}"
+  end
+
+  # Provide a default URL as a default if there hasn't been a file uploaded:
+  # def default_url
+  #   # For Rails 3.1+ asset pipeline compatibility:
+  #   # ActionController::Base.helpers.asset_path("fallback/" + [version_name, "default.png"].compact.join('_'))
+  #
+  #   "/images/fallback/" + [version_name, "default.png"].compact.join('_')
+  # end
+
+  # Process files as they are uploaded:
+  # process :scale => [200, 300]
+  #
+  # def scale(width, height)
+  #   # do something
+  # end
+
+
+  # Add a white list of extensions which are allowed to be uploaded.
+  # For images you might use something like this:
+  def extension_white_list
+    %w[pdf]
+  end
+
+  # Override the filename of the uploaded files:
+  # Avoid using model.id or version_name here, see uploader/store.rb for details.
+  # def filename
+  #   # "avatar.#{file.extension}" if original_filename
+  # end
+end
diff --git a/app/views/api/events/_event.json.jbuilder b/app/views/api/events/_event.json.jbuilder
index d3f0499ee..51098ee40 100644
--- a/app/views/api/events/_event.json.jbuilder
+++ b/app/views/api/events/_event.json.jbuilder
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 json.extract! event, :id, :title, :description, :age_range_id
 json.event_image event.event_image.attachment_url if event.event_image
 json.event_files_attributes event.event_files do |f|
@@ -6,18 +8,22 @@ json.event_files_attributes event.event_files do |f|
   json.attachment_url f.attachment_url
 end
 json.category_id event.category_id
-json.category do
-  json.id event.category.id
-  json.name event.category.name
-end if event.category
+if event.category
+  json.category do
+    json.id event.category.id
+    json.name event.category.name
+  end
+end
 json.event_theme_ids event.event_theme_ids
 json.event_themes event.event_themes do |e|
   json.name e.name
 end
 json.age_range_id event.age_range_id
-json.age_range do
-  json.name event.age_range.name
-end if event.age_range
+if event.age_range
+  json.age_range do
+    json.name event.age_range.name
+  end
+end
 json.start_date event.availability.start_at
 json.start_time event.availability.start_at
 json.end_date event.availability.end_at
@@ -25,7 +31,7 @@ json.end_time event.availability.end_at
 json.month t('date.month_names')[event.availability.start_at.month]
 json.month_id event.availability.start_at.month
 json.year event.availability.start_at.year
-json.all_day event.availability.start_at.hour == 0 ? 'true' : 'false'
+json.all_day event.availability.start_at.hour.zero? ? 'true' : 'false'
 json.availability do
   json.id event.availability.id
   json.start_at event.availability.start_at