Port of RSolr to Elixir

1. Add exsolr to your list of dependencies in mix.exs:

   def deps do [{:exsolr, git: "http://github.com/dcarneiro/exsolr"}] end

2. Ensure exsolr is started before your application:

   def application do [applications: [:exsolr]] end

The default behaviour is to configure using the config file:

In config/config.exs, add:

    config :exsolr,
      hostname: "localhost",
      port: 8983,
      core: "elixir_test"

Use #get to perform a query into Solr. All parameters are optional

    response = Exsolr.get(q: "roses", fq: ["blue", "violet"])
    Enum.map(response["docs"], fn(doc) -> doc["id"] end)

The following query fields will have default values if they aren't specified

    q:     "*:*"
    wt:    "json"
    start: 0
    rows:  10

Single document via #add

    Exsolr.add(%{id: 1, price: 1.00})

Multiple documents via #add

    [%{id: 1, price: 1.00}, %{id: 2, price: 10.50}]
    |> Exsolr.add

Force a commit into Solr

    Exsolr.commit

Delete by id

    Exsolr.delete_by_id("1")

Delete all the documents from the core

    Exsolr.delete_all