How can I fix this error in my code? : getting error on expecting key word

class Listing < ActiveRecord::Base
	
	 if Rails.env.development?
    has_attached_file :image, :styles => { :medium => "200", :thumb => "100x100>" }, :default_url => "default.jpg"
    validates_attachment_content_type :image, :content_type => /\Aimage\/.*\Z/
      else
    has_attached_file :image, :styles => { :medium => "200", :thumb => "100x100>" }, :default_url => "default.jpg",
    validates_attachment_content_type :image, :content_type => /\Aimage\/.*\Z/
                    :storage => :dropbox,
                    
                    :dropbox_credentials => Rails.root.join("config/dropbox.yml"),
                    :path => ":style/:id_filename"
  end
	    

	

	 validates :name, :description, :price, :address, :phone, presence: true 
	 validates :price, numericality: { greater_than: 0}
	 validates :phone, length: { maximum: 14 }
	
	 validates_attachment_presence :image
	 belongs_to :user
end
