Add some documentation, update the README.md

This is the first barely usable version of port_compiler. The README has
been updated in anticipation of soliciting testing by other folks.

Signed-off-by: Brian L. Troutwine <[email protected]>

Author: blt

CONTRIBUTING.md

@@ -0,0 +1,9 @@
+## How to Contribute
+
+Things that would be fine indeed:
+
+   * pull requests
+   * issue tickets
+   * emails with questions and/or concerns to `[email protected]`
+
+`<3`

README.md

@@ -1,26 +1,28 @@
 port_compiler
 =====
 
-a rebar3 port compiler for native code
+A port compiler for rebar3.
 
-Build
------
-
-    $ rebar3 compile
+This plugin is intended to replicate the rebar2 support for compiling native
+code. It is not a drop-in replacement in terms of command-line interface but the
+exact configuration interface in projects' `rebar.config`s have been preserved.
 
 Use
 ---
 
-Add the plugin to your rebar config:
+Add the plugin to your `rebar.config`:
 
     {plugins, [
-        { port_compiler, ".*", {git, "git@host:user/port_compiler.git", {tag, "0.1.0"}}}
+        { pc, {git, "git@github.com:blt/port_compiler.git", {tag, "0.1.0"}}}
     ]}.
 
-Then just call your plugin directly in an existing application:
+From your existing application:
+
 
+    $ rebar3 pc compile
+    ===> Fetching pc
+    ===> Compiling pc
+    ===> Verifying dependencies...
+    Compiling ...
 
-    $ rebar3 port_compiler
-    ===> Fetching port_compiler
-    ===> Compiling port_compiler
-    <Plugin Output>
+You should now have native code compiled.

src/pc.erl

@@ -93,13 +93,13 @@
 -spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
 init(State) ->
     Provider = providers:create([
-                                 {name, ?PROVIDER},           % The 'user friendly' name of the task
-                                 {module, ?MODULE},           % The module implementation of the task
-                                 {bare, true},                % The task can be run by the user, always true
-                                 {deps, ?DEPS},               % The list of dependencies
-                                 {example, "rebar pc"}, % How to use the plugin
-                                 {opts, []},                  % list of options understood by the plugin
-                                 {short_desc, "a rebar3 port compiler for native code"},
+                                 {name, ?PROVIDER},             %% The 'user friendly' name of the task
+                                 {module, ?MODULE},             %% The module implementation of the task
+                                 {bare, true},                  %% The task can be run by the user, always true
+                                 {deps, ?DEPS},                 %% The list of dependencies
+                                 {example, "rebar pc compile"}, %% How to use the plugin
+                                 {opts, []},                    %% list of options understood by the plugin
+                                 {short_desc, "A port compiler for rebar3."},
                                  {desc, ""}
                                 ]),
     {ok, rebar_state:add_provider(State, Provider)}.