CAS + SAML authentication feature (#6425)

* Cas authentication feature

* Config

* Remove class_eval + Omniauth initializer

* Codeclimate review

* Codeclimate review 2

* Codeclimate review 3

* Remove uid/email reconciliation

* SAML authentication

* Clean up code

* Improve login form

* Fix code style issues

* Add locales

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: 20180109143959) do
+ActiveRecord::Schema.define(version: 20180204034416) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -173,6 +173,15 @@ ActiveRecord::Schema.define(version: 20180109143959) do
     t.index ["account_id", "target_account_id"], name: "index_follows_on_account_id_and_target_account_id", unique: true
   end
 
+  create_table "identities", id: :serial, force: :cascade do |t|
+    t.integer "user_id"
+    t.string "provider", default: "", null: false
+    t.string "uid", default: "", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["user_id"], name: "index_identities_on_user_id"
+  end
+
   create_table "imports", force: :cascade do |t|
     t.integer "type", null: false
     t.boolean "approved", default: false, null: false
@@ -526,6 +535,7 @@ ActiveRecord::Schema.define(version: 20180109143959) do
   add_foreign_key "follow_requests", "accounts", name: "fk_76d644b0e7", on_delete: :cascade
   add_foreign_key "follows", "accounts", column: "target_account_id", name: "fk_745ca29eac", on_delete: :cascade
   add_foreign_key "follows", "accounts", name: "fk_32ed1b5560", on_delete: :cascade
+  add_foreign_key "identities", "users", on_delete: :cascade
   add_foreign_key "imports", "accounts", name: "fk_6db1b6e408", on_delete: :cascade
   add_foreign_key "invites", "users", on_delete: :cascade
   add_foreign_key "list_accounts", "accounts", on_delete: :cascade