Add first part of the tutorial

docs/tutorial/part-1.rst

@@ -3,6 +3,53 @@
 Create your first schema
 ========================
 
+What is a schema?
+-----------------
 
-TODO: explain what a schema is
-TODO: explain what a query is
+A GraphQL schema describes your data model, and provides a GraphQL
+server with an associated set of resolve methods that know how to fetch
+data.
+
+For a more in depth explaination you can refer to
+`the GraphQL documentation <http://graphql.org/learn/schema/>`_.
+
+Let's start by creating a simple schema with a ``Query`` that has only
+one field: ``hello``. When we query it will return ``"Hello world"``.
+
+Let's create a ``schema.py`` file and let's add the following content in it:
+
+
+.. code:: python
+
+    import graphene
+
+    class Query(graphene.ObjectType):
+        hello = graphene.String()
+
+        def resolve_hello(self, info):
+            return 'Hello world'
+
+        schema = graphene.Schema(query=Query)
+
+All GraphQL schemas are typed, so we need to specify the types in python.
+We do this by creating a ``Query`` class that extends ``graphene.ObjectType``,
+which is Graphene's way to specify a GraphQL type.
+
+We are specifying a single field in our Query. This field will be called ``hello``
+and will be of type ``String``.
+
+For each field then we have to specify a resolver method. In this case we are
+creating a basic method called ``resolve_hello`` that just returns ``"Hello world"``.
+
+Using the schema
+----------------
+
+Then we can start querying our schema:
+
+.. code:: python
+
+    result = schema.execute('{ hello }')
+    print(result.data['hello']) # "Hello world"
+
+Later we will show you how to serve the schema under an HTTP endpoint
+so that it can be used with JavaScript clients.