Fix #431 - convert gif to webm during upload. Web UI treats them like it did

before. In the API, attachments now can be either image, video or gifv. Gifv
is to be treated like images in terms of behaviour, but are videos by file
type.

db/migrate/20170304202101_add_type_to_media_attachments.rb

@@ -0,0 +1,12 @@
+class AddTypeToMediaAttachments < ActiveRecord::Migration[5.0]
+  def up
+    add_column :media_attachments, :type, :integer, default: 0, null: false
+
+    MediaAttachment.where(file_content_type: MediaAttachment::IMAGE_MIME_TYPES).update_all(type: MediaAttachment.types[:image])
+    MediaAttachment.where(file_content_type: MediaAttachment::VIDEO_MIME_TYPES).update_all(type: MediaAttachment.types[:video])
+  end
+
+  def down
+    remove_column :media_attachments, :type
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20170303212857) do
+ActiveRecord::Schema.define(version: 20170304202101) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -98,6 +98,7 @@ ActiveRecord::Schema.define(version: 20170303212857) do
     t.datetime "created_at",                     null: false
     t.datetime "updated_at",                     null: false
     t.string   "shortcode"
+    t.integer  "type",              default: 0,  null: false
     t.index ["shortcode"], name: "index_media_attachments_on_shortcode", unique: true, using: :btree
     t.index ["status_id"], name: "index_media_attachments_on_status_id", using: :btree
   end