Adds support for hex, ex_doc, and Elixir

Elixir is a popular alternative on the BEAM, and by supporting those
users as park of the RAIK ecosystem we can bring Riak to even more
peojects.

In order to generate docs run `rebar ex_doc`. This builds documentation
and places it in a `doc` folder. Open `doc/index.html` to view the
generated documentation.

I have set up the framework so that we can publish this to hex and get
more exposure.

Author: adkron

.gitignore

@@ -18,3 +18,4 @@ logs
 *.iml
 rebar3.crashdump
 *~
+doc/

README.md

@@ -54,7 +54,7 @@ ok
 ```
 
 With 8 nodes and 4 locations at your proposal, you can get a target n-val of 8 and a location nval of 4.
-That means that you can configure the system in such a way that you can loose 3 locations or 3 nodes and
+That means that you can configure the system in such a way that you can lose 3 locations or 3 nodes and
 still have one copy of all data available. Moreover, you have enough additional nodes to act take over the role of the lost nodes.
 
 ## Rebar3 plugin
@@ -81,3 +81,23 @@ Usage: rebar3 ring_calculator [-s <ring_size>] [-n <nodes>]
   -v, --verbose    print computation details
 ```
 
+## Elixir
+
+```elixir
+iex> Mix.install([{:ring_calculator, [github: "OpenRiak/ring_calculator", branch: "main"]}])
+iex> :ring_calculator.nvals(32, 8, 3)
+........................................x
+Best solution:
+Target Nval 8
+Location val 2
+Config [4,4]
+Ring: A1 B1 A2 B2 A3 B3 A4 B4 A1 B1 A2 B2 A3 B3 A4 B4 A1 B1 A2 B2 A3 B3 A4 B4 A1 B1 A2 B2 A3 B3 A4 B4 (0 violations)
+:ok
+```
+
+If you would like to be able to use `ring_calculator` from a mix project you can add the following
+dependency to your `mix.exs` deps.
+
+```elixir
+{:ring_calculator, github: "OpenRiak/ring_calculator", runtime: false}
+```

rebar.config

@@ -1,2 +1,10 @@
 {erl_opts, [debug_info]}.
-{deps, []}.
+{deps, []}.
+{plugins, [rebar3_hex, rebar3_ex_doc]}.
+{hex, [{doc, #{provider => ex_doc}}]}.
+{ex_doc, [
+    {source_url, <<"https://github.com/OpenRiak/ring_calculator">>},
+    {homepage_url, <<"https://github.com/OpenRiak/ring_calculator">>},
+    {extras, [<<"README.md">>, <<"LICENSE">>]},
+    {main, <<"README.md">>}
+]}.

src/ring_calculator.app.src

@@ -9,5 +9,7 @@
     {env, []},
     {modules, []},
     {licenses, ["Apache-2.0"]},
-    {links, []}
+    {links, [
+        {"GitHub", "https://github.com/OpenRiak/ring_calculator"}
+    ]}
  ]}.