heroku failing to deploy my app - ruby-on-rails

Question

I am not able to push my rails app on heroku. Below is error message i get when i try to push rails app on heroku.
Ruby app detected Compiling Ruby/Rails sh: 1: Gemfile: not found ! !
There was an error parsing your Gemfile, we cannot continue ! !
[!] There was an error parsing Gemfile: syntax error, unexpected
':', expecting end-of-input - group: production do ! ^. Bundler
cannot continue. ! ! # from
/tmp/build_c114d933dd903e377866500bea22e827/Gemfile:50 ! #
------------------------------------------- ! # ! > group: production do ! # gem 'pg' ! #
------------------------------------------- ! ! Push rejected, failed to compile Ruby app.
This is what my gemfile looks like.
source 'https://rubygems.org'
# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.2.5.1'
# Use sqlite3 as the database for Active Record
# Use SCSS for stylesheets
gem 'sass-rails', '~> 5.0'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# Use CoffeeScript for .coffee assets and views
gem 'coffee-rails', '~> 4.1.0'
# See https://github.com/rails/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby
# Use jquery as the JavaScript library
gem 'jquery-rails'
# Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
gem 'turbolinks'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.0'
# bundle exec rake doc:rails generates the API under doc/api.
gem 'sdoc', '~> 0.4.0', group: :doc
# Use ActiveModel has_secure_password
# gem 'bcrypt', '~> 3.1.7'
# Use Unicorn as the app server
# gem 'unicorn'
# Use Capistrano for deployment
# gem 'capistrano-rails', group: :development
group :development, :test do
gem 'sqlite3'
# Call 'byebug' anywhere in the code to stop execution and get a debugger console
gem 'byebug'
end
group :development do
# Access an IRB console on exception pages or by using <%= console %> in views
gem 'web-console', '~> 2.0'
# Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
gem 'spring'
end
group: production do
gem 'pg'
gem 'rails_12factor'
end

Answer 1

here was an error parsing Gemfile: syntax error, unexpected ':', expecting end-of-input - group: production
As above log...It is Just syntax error
group: production do
gem 'pg'
gem 'rails_12factor'
end
update it from
group :production do
gem 'pg'
gem 'rails_12factor'
end

Answer 2

Ok I figured it out. You are getting this error because of two mistakes you made in your gem file
(1) you forgot to define version of your gem 'byebug' in your gem file.
(2) you wrotegroup: production do which suppose to be group :production doI am pretty sure you will not be able to run your app locally either until you fix these both issues.
Add gem 'byebug', '3.4.0' in your gem file. you only have gem 'byebug' if you just add '3.4.0' secondly write group :production do instead of group: production do at 4th line from bottom of your gem file
once you add make these changes to your gem file make sure you run bundle install then bundle update
after successfully you do above process you can run below command to upload your app to heroku.
git init
git add .
git commit -am "some comment"
git push heroku master
heroku open