Add a `U2fRegistrations` table/model.

- To hold registrations from U2F devices, and to authenticate them.
- Previously, `User#two_factor_enabled` was aliased to the
  `otp_required_for_login` column on `users`.
- This commit changes things a bit:
    - `User#two_factor_enabled` is not a method anymore
    - `User#two_factor_enabled?` checks both the
      `otp_required_for_login` column, as well as `U2fRegistration`s
    - Change all instances of `User#two_factor_enabled` to
      `User#two_factor_enabled?`
- Add the `u2f` gem, and implement registration/authentication at the
  model level.

2 files changed, 27 insertions, 1 deletions

diff --git a/db/migrate/20160425045124_create_u2f_registrations.rb b/db/migrate/20160425045124_create_u2f_registrations.rb
new file mode 100644
index 00000000000..93bdd9de2eb
--- /dev/null
+++ b/db/migrate/20160425045124_create_u2f_registrations.rb
@@ -0,0 +1,13 @@
+class CreateU2fRegistrations < ActiveRecord::Migration
+  def change
+    create_table :u2f_registrations do |t|
+      t.text :certificate
+      t.string :key_handle, index: true
+      t.string :public_key
+      t.integer :counter
+      t.references :user, index: true, foreign_key: true
+
+      t.timestamps null: false
+    end
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 28902119615..9b991f347a9 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -12,7 +12,6 @@
 # It's strongly recommended that you check this file into your version control system.
 
 ActiveRecord::Schema.define(version: 20160530150109) do
-
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
   enable_extension "pg_trgm"
@@ -940,6 +939,19 @@ ActiveRecord::Schema.define(version: 20160530150109) do
   add_index "todos", ["target_type", "target_id"], name: "index_todos_on_target_type_and_target_id", using: :btree
   add_index "todos", ["user_id"], name: "index_todos_on_user_id", using: :btree
 
+  create_table "u2f_registrations", force: :cascade do |t|
+    t.text     "certificate"
+    t.string   "key_handle"
+    t.string   "public_key"
+    t.integer  "counter"
+    t.integer  "user_id"
+    t.datetime "created_at",  null: false
+    t.datetime "updated_at",  null: false
+  end
+
+  add_index "u2f_registrations", ["key_handle"], name: "index_u2f_registrations_on_key_handle", using: :btree
+  add_index "u2f_registrations", ["user_id"], name: "index_u2f_registrations_on_user_id", using: :btree
+
   create_table "users", force: :cascade do |t|
     t.string   "email",                       default: "",    null: false
     t.string   "encrypted_password",          default: "",    null: false
@@ -1047,4 +1059,5 @@ ActiveRecord::Schema.define(version: 20160530150109) do
   add_index "web_hooks", ["created_at", "id"], name: "index_web_hooks_on_created_at_and_id", using: :btree
   add_index "web_hooks", ["project_id"], name: "index_web_hooks_on_project_id", using: :btree
 
+  add_foreign_key "u2f_registrations", "users"
 end