Add tutorials main page

Author: domna

docs/tutorial/index.md

@@ -1 +1,8 @@
-# Tutorials
+# Tutorials
+
+Our tutorials provide step-by-step guides for getting started with pyElli.
+We tried to keep everything simple and unambigious, while still providing the necessary details for understanding how things work.
+
+A great first step is to follow the [performing a simple fit tutorial](simple_fit.md).
+The [working with dispersion models](working_with_dispersions.md) covers goes through using pre-built dispersion models,
+load literature values from [refractiveindex.info](https://refractiveindex.info) and explains how to built your own dispersion model.

mkdocs.yml

@@ -7,8 +7,12 @@ theme:
   name: material
   features:
     - navigation.instant
+    - navigation.instant.progress
+    - navigation.path
     - navigation.tabs
     - navigation.indexes
+    - navigation.footer
+    - navigation.top
     - content.code.copy
   palette:
     primary: cyan