First stab at documentation.

docs/index.rst

@@ -57,6 +57,7 @@ This library is framework agnostic and can be integrated in any PHP project, in
    Requirements <pages/requirements>
    Installation <pages/installation>
    Usage <pages/usage>
+   API <pages/api>
    Tests <pages/tests>
    Contributing <pages/contributing>
    Development <pages/development>

docs/pages/api.rst

@@ -0,0 +1,112 @@
+API
+===
+
+append
+------
+
+.. code-block:: php
+
+    $collection = Collection::with(['1', '2', '3']);
+
+    $collection
+        ->append('4'); // ['1', '2', '3', '4']
+
+    $this
+        ->append('5', '6'); // ['1', '2', '3', '5', '6']
+
+
+apply
+-----
+
+chunk
+-----
+
+collapse
+--------
+
+combine
+-------
+
+distinct
+--------
+
+explode
+-------
+
+filter
+------
+
+flatten
+-------
+
+flip
+----
+
+forget
+------
+
+intersperse
+-----------
+
+keys
+----
+
+limit
+-----
+
+map
+---
+
+merge
+-----
+
+normalize
+---------
+
+nth
+---
+
+only
+----
+
+pad
+---
+
+pluck
+-----
+
+prepend
+-------
+
+rebase
+------
+
+reduction
+---------
+
+reverse
+-------
+
+skip
+----
+
+slice
+-----
+
+sort
+----
+
+split
+-----
+
+tail
+----
+
+until
+-----
+
+walk
+----
+
+zip
+---