diff --git a/MANIFEST.in b/MANIFEST.in
new file mode 100644
index 0000000..e92a51b
--- /dev/null
+++ b/MANIFEST.in
@@ -0,0 +1,4 @@
+include requirements.txt
+include LICENSE
+include README.md
+prune tests
diff --git a/safrs/db.py b/safrs/db.py
index 8054f68..b93ad4e 100644
--- a/safrs/db.py
+++ b/safrs/db.py
@@ -26,6 +26,7 @@
 from sqlalchemy.types import Text, String, Integer, DateTime, TypeDecorator, Integer
 from sqlalchemy.ext.hybrid import hybrid_property
 from flask_marshmallow import Marshmallow
+from sqlalchemy import inspect as sqla_inspect
 
 from werkzeug import secure_filename
 from flask_sqlalchemy import SQLAlchemy
@@ -104,22 +105,6 @@ def _s_query(cls):
 
     query = _s_query
 
-    @classproperty
-    def _s_column_names(cls):
-        return [ c.name for c in cls.__mapper__.columns]
-    
-    @classproperty
-    def _s_columns(cls):
-        return list(cls.__mapper__.columns)
-
-    @classproperty
-    def _s_class_name(cls):
-        return cls.__tablename__
-
-    @classproperty
-    def _s_type(cls):
-        return cls.__tablename__
-
     def __new__(cls, **kwargs):
         '''
             If an object with given arguments already exists, this object is instantiated
@@ -139,10 +124,6 @@ def __new__(cls, **kwargs):
             
         return instance
 
-    @property
-    def _s_relationships(self):
-        return self.__mapper__.relationships
-
     def __init__(self, *args, **kwargs ):
         '''
             Object initialization: 
@@ -187,6 +168,7 @@ def __init__(self, *args, **kwargs ):
                 for rel_param in rel_params:
                     rel_object = rel.mapper.class_(**rel_param)
                     rel_attr.append(rel_object)
+        
 
         db.session.add(self)
         try:
@@ -195,6 +177,31 @@ def __init__(self, *args, **kwargs ):
             # Exception may arise when a db constrained has been violated (e.g. duplicate key)
             raise GenericError(str(exc))
 
+
+    def _s_expunge(self):
+        session = sqla_inspect(self).session
+        session.expunge(self)
+        
+    @classproperty
+    def _s_column_names(cls):
+        return [ c.name for c in cls.__mapper__.columns]
+    
+    @classproperty
+    def _s_columns(cls):
+        return list(cls.__mapper__.columns)
+
+    @classproperty
+    def _s_class_name(cls):
+        return cls.__tablename__
+
+    @classproperty
+    def _s_type(cls):
+        return cls.__tablename__
+
+    @property
+    def _s_relationships(self):
+        return self.__mapper__.relationships
+
     def _s_patch(self, **kwargs):
         for attr in self._s_column_names:
             value = kwargs.get(attr,None)
@@ -459,3 +466,6 @@ def get_db():
 
 db = get_db()
 ma = Marshmallow()
+
+
+
diff --git a/setup.cfg b/setup.cfg
new file mode 100644
index 0000000..6e20689
--- /dev/null
+++ b/setup.cfg
@@ -0,0 +1,16 @@
+[build_sphinx]
+source-dir = docs/source
+build-dir  = docs/build
+all_files  = 1
+
+[upload_sphinx]
+upload-dir = doc/build/html
+
+[metadata]
+description-file = README.md
+
+[zest.releaser]
+create-wheel = yes
+
+[aliases]
+test=pytest
diff --git a/setup.py b/setup.py
index dbf0ab2..8c9aef9 100644
--- a/setup.py
+++ b/setup.py
@@ -1,8 +1,13 @@
 from distutils.core import setup
+from pip.req import parse_requirements
+
+
+install_requires=[str(ir.req) for ir in parse_requirements('requirements.txt', session=False)]
+
 setup(
   name = 'safrs',
   packages = ['safrs'],
-  version = '1.0.2',
+  version = '1.0.3',
   license = 'MIT',
   description = 'safrs : SqlAlchemy Flask-Restful Swagger2',
   author = 'Thomas Pollet',
@@ -11,6 +16,7 @@
   download_url = 'https://github.com/thomaxxl/safrs/archive/1.0.1.tar.gz', 
   keywords = ['SqlAlchemy', 'Flask', 'REST', 'Swagger', 'JsonAPI', 'OpenAPI'], 
   python_requires='>=2.6, !=3.0.*, !=3.1.*, !=3.2.*, <4',
+  install_requires=install_requires,
   classifiers = [
         'Development Status :: 3 - Alpha',
         'License :: OSI Approved :: MIT License',