Add experimental identity api

Add docs to npmignore

.npmignore

@@ -1,6 +1,7 @@
 node_modules
 test
 *.spec.js
+docs
 
 .travis.yml
 .jshintignore

docs/API.md

@@ -6,7 +6,7 @@ crocks.js API
     * Async
     * Const
     * Either
-    * Identity
+    * [Identity](crocks/Identity.md)
     * IO
     * List
     * Maybe

docs/crocks/Identity.md

@@ -0,0 +1,63 @@
+# Identity
+
+`Identity : a -> a`
+
+It's just a function which returns what you pass into it.
+
+## What a crock!
+
+It converts your `non-crock` into a `crock`
+
+```js
+const frozenPizza = Identity('pizza') //Identity pizza
+const microwave = x => 'microwave ' + x
+const dinner = frozenPizza.map(microwave) //Identity "microwave pizza"
+dinner.value() // "microwave pizza"
+```
+
+| Constructor | Instance |
+|:---|:---|
+| [`of`](#of) | [`ap`](#ap), [`chain`](#chain), [`equals`](#equals), [`map`](#map), [`of`](#of), [`sequence`](#sequence), [`traverse`](#traverse), [`value`](#value) |
+
+## Constructors
+
+### of
+
+```js
+crocks.Identity.of([1,2,10])
+crocks.Identity([1,2,10])
+```
+
+## Instances
+
+### ap
+
+`Function (a -> b) -> Function b`
+
+### chain
+
+`(a -> m b) -> m b`
+
+### equals
+
+`x -> Boolean`
+
+### map
+
+`(a -> b) -> Function b`
+
+### of
+
+`a -> Function a`
+
+### sequence
+
+`Type (m a) -> m (Type a)`
+
+### traverse
+
+`a -> Function b -> Function b`
+
+### value
+
+`a -> a`