Shoes error writing to file

I am writing a program that will write a diary for the user, however i'm having a bit of trouble... Here's my code:

Shoes.app :title => "Diario", :width => 640, :height => 430 do
name = ask("Name")

n1 = ask("Yesterday's Date")

n2 = ask("Today's Date")

n3 = ask("Tommorow's Date")

w1 = ask("Yesterday's weather")
w2 = ask("Today's Weather")

w3 = ask("Tommorow's Weather")

a1 = ask("Yesterday's Activity")
a2 = ask("Today's Activity")

a3 = ask("Tommorow's Activity")

m = ask("Mood")

tw = ask("Today was...")
sn = ask("Special Notes")

@entry
para "Dear diary, The date is " + n2  + ". It is " + w2 + ". I will go to " + a2 + "."
para "Yesterday was " + n1  + ". It is " + w1 + ". I will go to " + a1 + "."
para "Tomorrow is " + n3  + ". It is " + w3 + ". I will go to " + a3 + "."
para "Today was " + tw + ". " + sn + "I am feeling " + m + "."
end

button "Save", :width => 85 do
    file = ask_save_file
    File.open(file, "w+") do |f|
        @file.text = File.write(@entry.text)
    end
end

- But when I run the code I get this-

Error in <unknown> line 0 | 2017-03-15 20:44:14 -0400
undefined method `button' for main:Object

I know this is an ametuer mistake, but please help me anyway? Thanks, Daniel M.

UPDATE: Problem solved; I just had to move the first 'END' to the end - it was closing the app block. However, When I save to a file now, it saves as a blank file... any ideas?

button is outside Shoes.app block

require 'shoes'

Shoes.app :title => "Diario", :width => 640, :height => 430 do
  name = ask("Name")

  n1 = ask("Yesterday's Date")

  n2 = ask("Today's Date")

  n3 = ask("Tommorow's Date")

  w1 = ask("Yesterday's weather")
  w2 = ask("Today's Weather")

  w3 = ask("Tommorow's Weather")

  a1 = ask("Yesterday's Activity")
  a2 = ask("Today's Activity")

  a3 = ask("Tommorow's Activity")

  m = ask("Mood")

  tw = ask("Today was...")
  sn = ask("Special Notes")

  @entry
  para "Dear diary, The date is " + n2  + ". It is " + w2 + ". I will go to " + a2 + "."
  para "Yesterday was " + n1  + ". It is " + w1 + ". I will go to " + a1 + "."
  para "Tomorrow is " + n3  + ". It is " + w3 + ". I will go to " + a3 + "."
  para "Today was " + tw + ". " + sn + "I am feeling " + m + "."

  button "Save", :width => 85 do
    file = ask_save_file
    File.open(file, "w+") do |f|
      @file.text = File.write(@entry.text)
    end
  end
end