Update introduction message in README.md and docs/index.rst

Author: joowani

README.md

@@ -9,10 +9,13 @@
 
 Are you studying binary trees for your next exam, assignment or technical interview?
 
-**Binarytree** is a Python library which lets you generate, visualize, inspect and 
-manipulate binary trees. Skip the tedious work of setting up test data, and dive 
-straight into practising your algorithms. Heaps and BSTs (binary search trees) are 
-also supported.
+**Binarytree** is a Python library which lets you generate, visualize, inspect and
+manipulate [binary trees](https://en.wikipedia.org/wiki/Binary_tree). Skip the tedious
+work of setting up test data, and dive straight into practising your algorithms.
+[Heaps](https://en.wikipedia.org/wiki/Heap_(data_structure)) and
+[binary search trees](https://en.wikipedia.org/wiki/Binary_search_tree) are also supported.
+Self-balancing search trees like [red-black](https://en.wikipedia.org/wiki/Red%E2%80%93black_tree)
+or [AVL](https://en.wikipedia.org/wiki/AVL_tree) will be added in the future.
 
 Check out the [documentation](http://binarytree.readthedocs.io) for more details.
 

docs/index.rst

@@ -11,9 +11,16 @@ Binarytree: Python Library for Studying Binary Trees
 Welcome to the documentation for **binarytree**.
 
 **Binarytree** is Python library which lets you generate, visualize, inspect and
-manipulate binary trees. Skip the tedious work of setting up test data, and dive
-straight into practising algorithms. Heaps and BSTs (binary search trees) are also
-supported.
+manipulate `binary trees`_. Skip the tedious work of setting up test data, and dive
+straight into practising algorithms. Heaps_ and `binary search trees`_ are also
+supported. Self-balancing search trees like `red-black`_ or `AVL`_ will be added in
+the future.
+
+.. _binary trees: https://en.wikipedia.org/wiki/Binary_tree
+.. _Heaps: https://en.wikipedia.org/wiki/Heap_(data_structure)
+.. _binary search trees: https://en.wikipedia.org/wiki/Binary_search_tree
+.. _red-black: https://en.wikipedia.org/wiki/Red%E2%80%93black_tree
+.. _AVL: https://en.wikipedia.org/wiki/AVL_tree
 
 Requirements
 ============