Generate spec/support/i18n.rb file

* Enable using just `t` (not `I18n.t`) in specs which was introduced in
  7ea5176 and removed in eaf7de1
* Add spec to ensure i18n support file is added
Set `en.titles.application` to App Name

* Gives developers that are unfamiliar with Caleb's `title` gem a nice hook to
  get started with
Do not ignore errors when checking for foreman

The `&>` syntax is not valid sh. Instead of changing it to valid sh
syntax (`2>&1 > /dev/null`), we can instead drop the `&` entirely.

If `command` prints to stderr, `foreman` may or may not be installed. In
this case the user will want to know that there was an error; telling
them that `foreman` is not installed masks the error, making debugging
trickier.
Raise unpermitted parameters in test environment

Unpermitted parameters were being raised in the development environment
but ignored in the test environment. That can cause specs to pass even
though performing the same steps in development will fail.

This change raises unpermitted parameters in all environments for
parity.
Raise on missing translations in test

Although we're generating a separate `spec/support/i18n.rb` file for i18n
(4d30479c3750ad5ce708cbf03ab8a58d484f2e8a), we're
once again **not** failing specs when a translation is missing.
Add normalize-rails to application.css.scss
Generate rails_helper, not spec_helper

RSpec 3.x introduces a `spec/rails_helper.rb` file
which contains all dependencies necessary to run specs that need Rails.

https://www.relishapp.com/rspec/rspec-rails/docs/upgrade#default-helper-files

Achieves the goal of "Documenting Explicit Dependencies Through Tests":

http://robots.thoughtbot.com/document-explicit-dependencies-through-tests

* Move Rails-specific things to rails_helper.rb.
* Require spec_helper.rb from rails_helper.rb.
* Remove duplication across files.
* We do not need to require "spec_helper" manually.
  It is required for us in `.rspec`:

    --color
    --warnings
    --require spec_helper
Generate a Rails 4.1.6 app
v1.17.0
Improve generated bin/setup

* Make script idempotent.
* Fail fast with install messages and non-zero exit status.
Remove unnecessary check for directory existence

`mkdir -p` will no-op if the directory already exists.
Use `uncomment_lines` Thor helper
Ignore the entire /tmp directory

This ignores the generated `tmp/heroku_commands` file instead of just the
`tmp/dummy` app.
Chome considers port 6000 unsafe

See http://superuser.com/questions/188058/which-ports-are-considered-unsafe-on-chrome
Use Ruby 2.1.3
Change `File.exists?` to `File.exist?`

* `File.exists?` is deprecated in favor of `File.exist?`

https://github.com/ruby/ruby/blob/trunk/file.c#L1482
Evaluates Ruby on generating `en.yml` locale file

In order to evaluate the Ruby code `<%= app_name.humanize %>` in
`templates/config_locales_en.yml` introduced in 4b0b8c1

* Change `config_locales_en.yml` to `config_locales_en.yml.erb`
* Use `template` when generating `config/locales/en.yml` file instead of
  copying the template file
* Add spec to ensure `en.titles.application` is set to App Name
Don't add staging/production remotes w/o access

If user doesn't have access to staging or production Heroku applications,
they do not need/want to have the Git remotes created.

Real-world example:

https://github.com/codecation/trailmix/pull/123
Promote NewRelic gem to global group
Fix accidental indentation

I created this when editing the previous commit.