Add Earnings Resource

[rodolfobandeira]

close #25

[rodolfobandeira]

@dblock Despite the fact it is passing on Travis, I have price_spec failing on my local machine. I'm not sure if you're getting the same thing? Would you mind to please confirm that?

Here is my log:

  1) IEX::Resources::Price known symbol retrieves a price
     Failure/Error: super JSON.parse(response[:body])['error']

     TypeError:
       no implicit conversion of nil into String
     # ./lib/iex/errors/client_error.rb:8:in `initialize'
     # ./lib/iex/resources/base.rb:9:in `exception'
     # ./lib/iex/resources/base.rb:9:in `raise'
     # ./lib/iex/resources/base.rb:9:in `rescue in symbol'
     # ./lib/iex/resources/base.rb:5:in `symbol'
     # ./lib/iex/resources/price.rb:7:in `get'
     # ./spec/iex/resources/price_spec.rb:6:in `block (3 levels) in <top (required)>'
     # ./spec/iex/resources/price_spec.rb:9:in `block (3 levels) in <top (required)>'
     # ------------------
     # --- Caused by: ---
     # Faraday::ParsingError:
     #   784: unexpected token at '93.78'
     #   ./lib/iex/api/price.rb:5:in `get'

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49 examples, 1 failure

[dblock]

LGTM, not sure what your local problem is, passes for me