finish fields docs intial ver,add test for related name, fix child_name(s) in reverse relations

docs_src/fields/docs002.py

@@ -0,0 +1,36 @@
+import databases
+import sqlalchemy
+
+import orm
+
+database = databases.Database("sqlite:///db.sqlite")
+metadata = sqlalchemy.MetaData()
+
+
+class Department(orm.Model):
+    __database__ = database
+    __metadata__ = metadata
+
+    id = orm.Integer(primary_key=True)
+    name = orm.String(length=100)
+
+
+class Course(orm.Model):
+    __database__ = database
+    __metadata__ = metadata
+
+    id = orm.Integer(primary_key=True)
+    name = orm.String(length=100)
+    completed = orm.Boolean(default=False)
+    department = orm.ForeignKey(Department, related_name="my_courses")
+
+department = Department(name='Science')
+course = Course(name='Math', completed=False, department=department)
+
+print(department.my_courses[0])
+# Will produce:
+# Course(id=None,
+#        name='Math',
+#        completed=False,
+#        department=Department(id=None, name='Science'))
+