Improve documentation

.gitignore

@@ -1,3 +1,4 @@
 .pytest_cache
 .tox
 docs/_build
+.vscode

README.rst

@@ -1,7 +1,7 @@
 django-pgtree
 =============
 
-A generic model for storing heirachial data in trees, using `PostgreSQL's built-in ltree data type <ltree_>`_, plus a ltree field for you to use on your own models.
+A generic model for storing hierarchical data in trees, using `PostgreSQL's built-in ltree data type <ltree_>`_, plus a ltree field for you to use on your own models.
 
 Supports Django 2.0+ on Python 3.5+.
 
@@ -29,3 +29,5 @@ Supports Django 2.0+ on Python 3.5+.
     [<Organism: Animal>, <Organism: Mammal>]
     >>> cat.siblings
     [<Organism: Dog>]
+    >>> Organism.objects.roots()
+    [<Organism: Animal>]

django_pgtree/dbext.py

@@ -0,0 +1,12 @@
+from django.contrib.postgres.operations import CreateExtension
+
+
+class LtreeExtension(CreateExtension):
+    """Django migration operation to add PostgreSQL extension LTree to our project."""
+
+    def __init__(self):
+        self.name = 'ltree'
+
+    def database_backwards(self, app_label, schema_editor, from_state, to_state):
+        # No need to drop extension
+        pass

docs/index.rst

@@ -1,15 +1,8 @@
+
 .. include:: ../README.rst
 
 .. toctree::
    :maxdepth: 2
 
    install
-
-
-
-Indices and tables
-==================
-
-* :ref:`genindex`
-* :ref:`modindex`
-* :ref:`search`
+   model

docs/install.rst

@@ -20,7 +20,7 @@ On your development database and when you first deploy, you'll also need to run
 
     CREATE EXTENSION ltree;
 
-This command needs to be run by the database superuser (usually the ``postgres`` user). If you know that your migrations will be run by this user, you can create a ``RunSQL`` migration that does this for you, but in most cases you'll need to do this when you create the database.
+This command needs to be run by the database superuser (usually the ``postgres`` user). If you know that your migrations will be run by this user, you can use our ``LtreeExtension`` migration operation (see more in :doc:`model`), but in most cases you'll need to do this when you create the database.
 
 .. tip::
 

docs/model.rst

@@ -12,7 +12,20 @@ This functionality is for when you want to model your data as a tree, of which m
     class Organism(TreeNode):
         name = models.CharField()
 
-You can create root nodes as you would any other normal model:
+If you haven't manually run the SQL query ``CREATE EXTENSION ltree`` before, you can do it in migration script:
+
+.. code-block:: python
+
+    from django_pgtree.dbext import LtreeExtension
+
+    class Migration(migrations.Migration):
+        operations = [
+            LtreeExtension(),
+            # Other migration operations
+        ]
+
+
+You can create root nodes as you would like any other normal model:
 
 .. code-block:: python
 

pyproject.toml

@@ -1,7 +1,7 @@
 [tool.poetry]
 name = "django-pgtree"
 version = "0.1.4"
-description = "Heirachial data for Django with Postgres."
+description = "Hierarchical data for Django with Postgres."
 authors = ["Adam Brenecki"]
 license = "ISC"
 

tox.ini

@@ -34,3 +34,4 @@ python_paths=testproject/
 
 [flake8]
 max_line_length = 88
+ignore = W503