To easily limit the execution of RSpec tests while you are developing use the
power of the `.rspec` opts file and RSpec tags.

Tags can be added to any RSpec method `describe`, `context`, `it`, etc.

The are simply arguments passed as a Hash to the method.

```ruby
describe 'foo', focus: true do
  context 'bar', slow: true do
    it 'uses the database', db: true do
```

The above example shows a couple different tags you can try. They can really be
any valid Ruby symbol but `:focus` and `:skip` are traditional.

You can call `rspec` to either run only the tags or to ignore the tags.

`be rspec --tag ~db` skips all the `:db` tagged specs.
`be rspec --tag focus` runs all the specs inside the `describe` block.

RSpec uses an opt file that can exist in your local directory and your home
directory. The home directory file sets your global defaults but the local file
will override those settings.

Copy and paste this into your command line to get started with running `:focus`
specs via tags instead of having to always pass a line number to your `rspec`
commands.

echo "--color
--no-profile
--format Fuubar
--deprecation-out log/rspec-deprecations.log
--tag focus" > ~/.rspec

Remove the `--tag focus` line to run all specs (hint the above snippet will
tell RSpec to *only* run `:focus` tagged specs).

Run `rspec --help` for more ways to customize your RSpec experience.