Implement EmailBlackList (#5109)

* Implement BlacklistedEmailDomain

* Use Faker::Internet.domain_name

* Remove note column

* Add frozen_string_literal comment

* Delete unnecessary codes

* Sort alphabetically

* Change of wording

* Rename BlacklistedEmailDomain to EmailDomainBlock

db/migrate/20170928082043_create_email_domain_blocks.rb

@@ -0,0 +1,9 @@
+class CreateEmailDomainBlocks < ActiveRecord::Migration[5.1]
+  def change
+    create_table :email_domain_blocks do |t|
+      t.string :domain, null: false
+
+      t.timestamps
+    end
+  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: 20170927215609) do
+ActiveRecord::Schema.define(version: 20170928082043) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -110,6 +110,12 @@ ActiveRecord::Schema.define(version: 20170927215609) do
     t.index ["domain"], name: "index_domain_blocks_on_domain", unique: true
   end
 
+  create_table "email_domain_blocks", force: :cascade do |t|
+    t.string "domain", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+  end
+
   create_table "favourites", force: :cascade do |t|
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false