update readme file

README.md

@@ -2,4 +2,87 @@
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-Django JSON Schema Field
+Django JSON Schema Field.
+
+## Table of content
+- [Introduction](#introduction)
+- [Installing](#installing)
+- [Usage](#usage)
+- [TODO](#TODO)
+
+## Introduction
+Django JSON Schema is a library for displaying and validating 
+postgresql jsonb data.
+
+## Installing
+```
+pip install django_json_schema
+```
+
+## Usage
+First you create a schema class.
+
+Schema class is a django abstract model class (abstract = True).
+
+You can import SchemaMeta class or create an abstract class.
+
+If you want to validate and display nested data you can do this with the SchemaForeignKey.
+
+For example to validating this dict data.
+```python
+{
+    'name': 'parent',
+    'age': 50,
+    'son': {
+        'name': 'son',
+        'age': '15',
+        'school': {
+            'name': 'school',
+            'address': 'school address'
+        }
+    }
+}
+```
+We create this three schema classes.
+
+We can use any django model or third party field.
+```python
+#schemas.py
+from json_schema.models import SchemaForeignKey, SchemaMeta
+
+
+class SchoolSchema(models.Model):
+    name = models.CharField(max_length=128)
+    address = models.CharField(max_length=128)
+    Meta = SchemaMeta()
+
+
+class SonSchema(models.Model):
+    name = models.CharField(max_length=128)
+    age = models.IntegerField()
+    school = SchemaForeignKey(SchoolSchema, on_delete=models.CASCADE)
+    Meta = SchemaMeta()
+
+
+class ParentSchema(models.Model):
+    name = models.CharField(max_length=128, default="test")
+    age = models.IntegerField()
+    son = SchemaForeignKey(SonSchema, on_delete=models.CASCADE)
+    Meta = SchemaMeta()
+```
+After we create our model.
+```python
+#models.py
+from django.db import models
+
+from json_schema.fields import JSONSchemaField
+from .schemas import ParentSchema
+
+class JSONSchemaModel(models.Model):
+    simple_text = models.CharField(blank=True, null=True, max_length=256)
+    simple_int = models.IntegerField(blank=True, null=True)
+    parent = JSONSchemaField(schema=ParentSchema, blank=True, schema_array=True)
+```
+
+##TODO
+Support array elements.