Add categories for custom emojis (#11196)

Fix #7940

db/migrate/20190627222225_create_custom_emoji_categories.rb

@@ -0,0 +1,9 @@
+class CreateCustomEmojiCategories < ActiveRecord::Migration[5.2]
+  def change
+    create_table :custom_emoji_categories do |t|
+      t.string :name, index: { unique: true }
+
+      t.timestamps
+    end
+  end
+end

db/migrate/20190627222826_add_category_id_to_custom_emojis.rb

@@ -0,0 +1,5 @@
+class AddCategoryIdToCustomEmojis < ActiveRecord::Migration[5.2]
+  def change
+    add_column :custom_emojis, :category_id, :bigint
+  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: 2019_05_29_143559) do
+ActiveRecord::Schema.define(version: 2019_06_27_222826) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -208,6 +208,13 @@ ActiveRecord::Schema.define(version: 2019_05_29_143559) do
     t.index ["uri"], name: "index_conversations_on_uri", unique: true
   end
 
+  create_table "custom_emoji_categories", force: :cascade do |t|
+    t.string "name"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["name"], name: "index_custom_emoji_categories_on_name", unique: true
+  end
+
   create_table "custom_emojis", force: :cascade do |t|
     t.string "shortcode", default: "", null: false
     t.string "domain"
@@ -221,6 +228,7 @@ ActiveRecord::Schema.define(version: 2019_05_29_143559) do
     t.string "uri"
     t.string "image_remote_url"
     t.boolean "visible_in_picker", default: true, null: false
+    t.bigint "category_id"
     t.index ["shortcode", "domain"], name: "index_custom_emojis_on_shortcode_and_domain", unique: true
   end