Merge branch 'master' into glitch-soc/merge-upstream

Conflicts:
- config/locales/en.yml
  Conflict caused by the glitch-soc-specific “flavour” string being too close
  to the newly introduced “identity_proofs” string. Just included both.

db/migrate/20190316190352_create_account_identity_proofs.rb

@@ -0,0 +1,16 @@
+class CreateAccountIdentityProofs < ActiveRecord::Migration[5.2]
+  def change
+    create_table :account_identity_proofs do |t|
+      t.belongs_to :account, foreign_key: { on_delete: :cascade }
+      t.string :provider, null: false, default: ''
+      t.string :provider_username, null: false, default: ''
+      t.text :token, null: false, default: ''
+      t.boolean :verified, null: false, default: false
+      t.boolean :live, null: false, default: false
+
+      t.timestamps null: false
+    end
+
+    add_index :account_identity_proofs, [:account_id, :provider, :provider_username], unique: true, name: :index_account_proofs_on_account_and_provider_and_username
+  end
+end