Add ability to use remote follow function on other sites

app/controllers/authorize_follow_controller.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+class AuthorizeFollowController < ApplicationController
+  layout 'public'
+
+  before_action :authenticate_user!
+
+  def new
+    @account = FollowRemoteAccountService.new.call(params[:acct])
+    render :error if @account.nil?
+  end
+
+  def create
+    @account = FollowService.new.call(current_account, params[:acct]).try(:target_account)
+
+    if @account.nil?
+      render :error
+    else
+      redirect_to web_url("accounts/#{@account.id}")
+    end
+  rescue ActiveRecord::RecordNotFound, Mastodon::NotPermitted
+    render :error
+  end
+end