Defining structure for the tutuorial

Author: myroslav

docs/source/tutorial.rst

@@ -3,6 +3,9 @@
 Tutorial
 ========
 
+Exploring basic rules
+---------------------
+
 Let's try exploring the `/tenders` endpoint:
 
 .. include:: tutorial/initial-tender-listing.http
@@ -24,6 +27,9 @@ Let's satisfy the Content-type requirement:
 
 Error states that no `data` found in JSON body.
 
+Creating tender
+---------------
+
 Let's provide the data attribute in the body submitted:
 
 .. include:: tutorial/tender-post-attempt-json-data.http
@@ -66,6 +72,9 @@ Let's check what tender registry contains:
 
 And indeed we have 2 tenders now.
 
+Modifying tender
+----------------
+
 Let's update tender by providing it with all other essential properties:
 
 .. include:: tutorial/patch-items-value-periods.http