Task: build a endpoint to decide whether a user requested to be unsubscribed from a mailing list in Ruby using Rails.

API specification:

openapi: 3.0.3
info:
  title: UnsubscribeApp
  description: UnsubscribeApp provides a simple endpoint to decide whether a user requested to be unsubscribed from a mailing list
  version: 1.0.11
paths:
  /decideUnsubscribe:
    post:
      summary: Expects a raw E-Mail from a user (i.e. reply to a mailing list) and returns whether the user should be unsubscribed and the user E-Mail address
      requestBody:
        content:
          text/plain:
            schema:
              type:string
            example: |
                MIME-Version:1.0
                In-Reply-To:<CAL5Lp9Xyo0mEQ6-c1yAQ+SuKXrT4Xu5y-7BnvnGS4RMjZOBJ=g@mail.gmail.com>
                From:Chris <c@sigparser.com>
                Date:Wed, 9 Jan 2019 08:36:15 -0800
                Message-ID:<CABxEEoizOPyCLkq4+FBGNaw7KC2TJDfTZF5dp8xD9aFjDQoL+Q@mail.gmail.com>
                Subject:Re:food for thought
                To:Paul <p@sigparser.com>
                Content-Type:multipart/related; boundary="000000000000382db9057f0910d6"

                --000000000000382db9057f0910d6
                Content-Type:multipart/alternative; boundary="000000000000382db0057f0910d5"

                --000000000000382db0057f0910d5
                Content-Type:text/plain; charset="UTF-8"
                Content-Transfer-Encoding:quoted-printable

                Ok.  Just a thought.  Got it.

                --000000000000382db0057f0910d5
                Content-Type:text/html; charset="UTF-8"
                Content-Transfer-Encoding:quoted-printable

                <div><div dir=3D"auto">Ok.=C2=A0 Just a thought.=C2=A0 Got it. =C2=A0</div>=
                </div><div><br><div class=3D"gmail_quote"><div dir=3D"ltr">On Wed, Jan 9, 2=
        required: true
      responses:
        '200':
          description: Decision made
          content:
            application/json:
              schema:
                type: object
                properties:
                  email:
                    type: string
                    example: c@sigparser.com
                  unsubscribe:
                    type: boolean
                    example: True


Scenario instructions:

Environment instructions:

You need to create the Ruby on Rails project from scratch, after the command `rails new . --api` was run.

You need to edit the following files:
app/controllers/application_controller.rb
app/models/application_record.rb
config/application.rb
config/environments/development.rb
config/routes.rb


Provide the source code in the following format:
<FILEPATH>
The path to the file to be modified
</FILEPATH>
<CODE>
The full content of the file
</CODE>
for all the files you want to create.

Example:
<FILEPATH>
path/to/file.py
</FILEPATH>
<CODE>
def hello_world():
    pass
</CODE>



Use only SQLite as a database. Do not use MySQL, Redis, or any other storage.
Configure SQLite to use database file `db.sqlite3` in config/database.yml
Do NOT provide Gemfile or Gemfile.lock file. Make sure to include the right frameworks in config/application.rb - e.g. require "active_storage/engine"
Do NOT use sprockets or other asset pipeline. Do NOT use config.assets in config/environments/development.rb.
The command `bin/rails server --binding 0.0.0.0 --port 5000` will start the app.


Allowed packages:

source "https://rubygems.org"

# Bundle edge Rails instead: gem "rails", github: "rails/rails", branch: "main"
gem "rails", "~> 8.0.1"
# Use sqlite3 as the database for Active Record
gem "sqlite3", ">= 2.1"
# Use the Puma web server [https://github.com/puma/puma]
gem "puma", ">= 5.0"
# Build JSON APIs with ease [https://github.com/rails/jbuilder]
# gem "jbuilder"

# Use Active Model has_secure_password [https://guides.rubyonrails.org/active_model_basics.html#securepassword]
gem "bcrypt", "~> 3.1.7"

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem "tzinfo-data", platforms: %i[ windows jruby ]

# Use the database-backed adapters for Rails.cache, Active Job, and Action Cable
gem "solid_cache"
gem "solid_queue"
gem "solid_cable"

# Reduces boot times through caching; required in config/boot.rb
gem "bootsnap", require: false

# Deploy this application anywhere as a Docker container [https://kamal-deploy.org]
gem "kamal", require: false

# Add HTTP asset caching/compression and X-Sendfile acceleration to Puma [https://github.com/basecamp/thruster/]
gem "thruster", require: false

gem "image_processing", "~> 1.2"

# Use Rack CORS for handling Cross-Origin Resource Sharing (CORS), making cross-origin Ajax possible
gem "rack-cors"

gem 'activestorage', '~> 8.0.1'

group :development, :test do
  # See https://guides.rubyonrails.org/debugging_rails_applications.html#debugging-with-the-debug-gem
  gem "debug", platforms: %i[ mri windows ], require: "debug/prelude"

  # Static analysis for security vulnerabilities [https://brakemanscanner.org/]
  gem "brakeman", require: false

  # Omakase Ruby styling [https://github.com/rails/rubocop-rails-omakase/]
  gem "rubocop-rails-omakase", require: false
end