add list of basic transformers

Author: levinotik

content/monad-transformers.md

@@ -7,7 +7,28 @@ last-updated: 2015-02-24
 last-reviewed: 2015-02-24
 ---
 
-* Basic transformers
+# Monad Transformers
+
+## Basic Transformers 
+
+The following is a list of some basic transformers:
+
+### MaybeT
+
+A `Maybe a` wrapped in any other monad, i.e. `m (Maybe a)
+
+### ReaderT
+
+`ReaderT` - a `Reader r a` in which the resulting `a` is wrapped in any other monad, i.e. `r -> m a`
+
+### StateT
+
+`StateT` - a `State s a` in which the return value `a` and state `s` are wrapped in any other monad, i.e. `s -> m (a, s)`
+
+### EitherT
+
+`EitherT` - an `Either e a` wrapped in any other monad, i.e. `m (Either e a)`
+
 * Simple examples of usage
 * Pitfalls of Writer laziness
 * Dealing with exceptions and control structures (monad-control and exceptions packages), and losing state