added first few introduction files

docs/index.rst

@@ -12,6 +12,25 @@ documentation for details.
 
 
 .. toctree::
-   :maxdepth: 2
+   :hidden:
-   :caption: Contents:
+   :maxdepth: 1
+   :caption: Linux
+   :name: sec-linux
 
+   linux/introduction
+
+.. toctree::
+   :hidden:
+   :maxdepth: 1
+   :caption: Python
+   :name: sec-python
+
+   python/introduction
+
+.. toctree::
+   :hidden:
+   :maxdepth: 1
+   :caption: PostgreSQL
+   :name: sec-postgresql
+
+   postgresql/introduction

docs/linux/introduction.rst

@@ -1,3 +1,3 @@
-Introduction to Linux
+Introduction
-=====================
+============
 

docs/postgresql/introduction.rst

@@ -1,3 +1,3 @@
-Introduction to PostgreSQL
+Introduction
-==========================
+============
 

docs/python/introduction.rst

@@ -1,3 +1,3 @@
-Introduction to Python
+Introduction
-======================
+============