Update Docs: add analysis workflow example

docs/index.rst

@@ -17,6 +17,7 @@ Contents:
    usage/introduction
    usage/installation
    usage/quick_rule
+   usage/example
    usage/snakemake_docs
    usage/faq
 

docs/usage/example.rst

@@ -0,0 +1,34 @@
+.. _analysis-workflow-example
+
+Analysis Workflow Example
+==========================
+
+This is a quick guide for creating and running a simple pipeline to analysis an example dataset with 2 participants.
+
+#. Install RAPIDS. See :ref:`Installation Section <install-page>`.
+
+#. Make sure your database connection credentials in ``.env`` have write permission and set the correct ``MY_GROUP`` parameter in ``config.yaml`` file. See step 1 of :ref:`Usage Section <db-configuration>`.
+
+#. Make sure your Conda (python) environment is active. See step 6 of :ref:`install-page`.
+
+#. Run the following command to restore database from ``rapids_example.sql`` file. 
+
+::
+    sankemake -j1 restore_sql_file
+
+
+#. Create example participants files with the following command.
+
+::
+
+    snakemake -j1 create_example_participant_files
+
+#. Run the following command to analysis the example dataset.
+
+    - Execute over a single core::
+
+        snakemake -j1 --profile example_profile
+
+    - Execute over multiple cores (here, we use 8 cores)::
+        snakemake -j8 --profile example_profile
+