Add documentation for usage as python module

docs/source/developer/developer_documentation.rst

@@ -16,6 +16,11 @@ Project Structure
 
 .. include:: project_structure.rst
 
+ESBO-ETC Python module
+======================
+
+.. include:: scripting.rst
+
 Software Architecture
 =====================
 

docs/source/developer/scripting.rst

@@ -0,0 +1,26 @@
+ESBO-ETC is designed to be included as module in other Python scripts.
+This is possible by importing the class ``esbo_etc`` from the module ``esbo_etc`` as shown below.
+
+.. code-block:: python
+    :linenos:
+
+    from esbo_etc import esbo_etc
+
+The class ``esbo_etc`` requires a path to the configuration file as initialization argument and some other optional paramaters.
+The created object offers the method ``run()`` to trigger the computation.
+The result of the computation is returned as Astropy quantity.
+A Minimal example looks as follows:
+
+.. code-block:: python
+    :linenos:
+
+    from esbo_etc import esbo_etc
+
+
+    # Initialize a new ESBO-ETC object
+    etc = esbo_etc("path_to_configuration_file.xml")
+
+    # Run the calculations
+    res = etc.run()
+
+    print(res)