```ruby
require "rails/generators"

module Suspenders
  class ErrorReportingGenerator < Rails::Generators::Base
    source_root File.expand_path(
      File.join("..", "..", "..", "templates"),
      File.dirname(__FILE__),
    )

    def add_sentry
      gem "sentry-raven"
      Bundler.with_clean_env { run "bundle install" }
    end

    def set_up_sentry
      copy_file "sentry.rb", "config/initializers/sentry.rb"
    end

    def configure_sentry_context
      inject_into_class(
        "app/controllers/application_controller.rb",
        'ApplicationController',
        context_configuration
      )
    end

    def env_vars
      expand_json(
        "app.json",
        env: {
          SENTRY_DSN: { required: true },
          SENTRY_CURRENT_ENV: { required: true }
        }
      )
    end

    private

    def context_configuration
      <<-RUBY
  before_action :set_raven_context

  private

  def set_raven_context
    Raven.user_context(id: session[:current_user_id])
    Raven.extra_context(params: params.to_unsafe_h, url: request.url)
  end
      RUBY
    end
  end
end
```

Fix bug: forgot to include module with env var json helper
user
```ruby
require "rails/generators"

module Suspenders
  class ErrorReportingGenerator < Rails::Generators::Base
    include Suspenders::Actions

    source_root File.expand_path(
      File.join("..", "..", "..", "templates"),
      File.dirname(__FILE__),
    )

    def add_sentry
      gem "sentry-raven"
      Bundler.with_clean_env { run "bundle install" }
    end

    def set_up_sentry
      copy_file "sentry.rb", "config/initializers/sentry.rb"
    end

    def configure_sentry_context
      inject_into_class(
        "app/controllers/application_controller.rb",
        'ApplicationController',
        context_configuration
      )
    end

    def env_vars
      expand_json(
        "app.json",
        env: {
          SENTRY_DSN: { required: true },
          SENTRY_CURRENT_ENV: { required: true }
        }
      )
    end

    private

    def context_configuration
      <<-RUBY
  before_action :set_raven_context

  private

  def set_raven_context
    Raven.user_context(id: session[:current_user_id])
    Raven.extra_context(params: params.to_unsafe_h, url: request.url)
  end
      RUBY
    end
  end
end
```
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