resend confirmation email with devise token auth gem

In overrides/confirmations_controller.rb:

module Overrides
  class ConfirmationsController < DeviseTokenAuth::ConfirmationsController

    def create
      unless params[:email]
        return render json: {
          success: false,
          errors: ['You must provide an email address.']
        }, status: 400
      end

      unless params[:redirect_url]
        return render json: {
          success: false,
          errors: ['Missing redirect url.']
        }, status: 400
      end

      if resource_class.case_insensitive_keys.include?(:email)
        email = params[:email].downcase
      else
        email = params[:email]
      end

      q = "uid = ? AND provider='email'"

      # fix for mysql default case insensitivity
      if ActiveRecord::Base.connection.adapter_name.downcase.starts_with? 'mysql'
        q = "BINARY uid = ? AND provider='email'"
      end

      @resource = resource_class.where(q, email).first

      errors = nil

      if @resource && @resource.confirmed?
        return render json: {
          success: false,
          errors: ['You email address is already confirmed.']
        }, status: 400
      end

      if @resource
        @resource.send_confirmation_instructions({
          redirect_url: params[:confirm_success_url],
          client_config: params[:config_name]
        })
      else
        errors = ["Unable to find user with email '#{email}'."]
      end

      if errors
        render json: {
          success: false,
          errors: errors
        }, status: 400
      else
        render json: {
          status: 'success',
          data:   @resource.as_json
        }
      end
    end
  end
end

In route:

mount_devise_token_auth_for 'User', at: 'auth', skip: [:omniauth_callbacks], :controllers => { confirmations: "overrides/confirmations", passwords: "overrides/passwords" }