Connect to Postgres on localhost

* Most installs listen on localhost
* Many installs do not listen on a socket
* This fixes connection errors for many users
Move SMTP variable settings out of initializer

Since we require the `smtp.rb` file in the environment files, and Rails loads it
as part of its boot process, this file was loaded twice. This causes a constant
reinitialization warning.

Also, to remove the duplicaton, there is no need to check the environment,
since we require the files from the appropriate environment files.

Fixes #335
Maintain ActiveRecord test schema

* Add ActiveRecord::Migration.maintain_test_schema! to rspec template
Unify Ruby version for gem and suspended apps

    One Ruby to rule them all, One Ruby to find them,
    One Ruby to bring them all and in the light bind them
    In the Land of .ruby-version where the Fluorescents lie.

When creating new apps, there is little reason to use an older version
of Ruby than the most recent. For most use cases, having the latest
version is going to be the best approach.

* Move Ruby version to .ruby-version for gem
* Read this file into Suspenders::RUBY_VERSION
* Use Suspenders::RUBY_VERSION everywhere we need it, such as the
* Gemfile and generated Travis config.
* Update README documentation about Ruby and Rails versions.
* Add color to Travis output.

This is based on a conversation with @derekprior and @mrgilman.
Escape Erb in secrets.yml

Fixes issue where `secret_key_base` in `config/secrets.yml` was blank,
missing `<%= ENV['SECRET_KEY_BASE'] %>`.

Fixes #340
Bump to 1.11.0
Create the .env file before running rake tasks.

In Rails apps which require an environment variable to be set in an
initializer, `rake dev:prime` will fail unless the `.env` file is put in
place first.
Ensure EMAIL_RECIPIENTS is set on staging

When the variable isn't set, mail deliveries will raise:

```
ArgumentError: An SMTP To address is required to send a message. Set the message
smtp_envelope_to, to, cc, or bcc address
```

I could cause head scratching, based on forgetting that staging intercepts
emails.
Add ActionMailer spec support file

Clears deliveries collection before each test
Include newrelic config file

* Fixes https://github.com/thoughtbot/suspenders/issues/287

Minor:

* Require 'net/http' to fix `download_file` method
Add newrelic config template

Minor:

* Remove unused `download_file` method
* Add newline before spec expectations