Adds Identity API to docs (#38)

* Add API documentation

.npmignore

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 node_modules
 test
 *.spec.js
+docs
 
 .npmignore
 .babelrc

docs/crocks/Identity.md

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+# Identity
+
+`Identity a`
+
+Crock which returns the same value that was used as its argument
+
+"`Identity`" creates linear data flow in comparison to imperative usage.
+
+```js
+// Imperative flow
+const capitalizeFirstLetter = string => {
+  const firstLetter = string.charAt(0)
+  const upppercasedLetter = firstLetter.toUpperCase()
+  return upppercasedLetter + string.slice(1);
+}
+
+// Declarative flow
+const capitalizeFirstLetter = string =>
+  Identity(string)
+    .map(str => str.charAt(0))
+    .map(char => char.toUpperCase())
+    .map(upper => upper + string.slice(1))
+    .value()
+```
+
+`Identity` exposes these constructors and instances:
+
+| Constructor | Instance |
+|:---|:---|
+| [`of`](#of) | [`inspect`](#inspect), [`value`](#value), [`type`](#type), [`equals`](#equals), [`map`](#map), [`ap`](#ap), [`of`](#of), [`chain`](#chain), [`sequence`](#sequence), [`traverse`](#traverse) |
+
+## Constructors
+
+### of
+
+`Identity m => a -> m a`
+
+## Instances
+
+### inspect
+
+`() => String`
+
+### value
+
+`Identity m => m a ~> () => a`
+
+### type
+
+`() -> String`
+
+### equals
+
+`a -> Boolean`
+
+### map
+
+`Identity m => m a ~> (a -> b) -> m b`
+
+### ap
+
+`Identity m => m (a -> b) ~> m a -> m b`
+
+### of
+
+`Identity m => a -> m a`
+
+### chain
+
+`Identity m => m a ~> (a -> m b) -> m b`
+
+### sequence
+
+`Identity m, Applicative f => m (f a) ~> (b -> f b) -> f (m a)`
+
+### traverse
+
+`Identity m, Applicative f => m a ~> (c -> f c) -> (a -> f b) -> f (m b)`