diff --git a/.bumpversion.cfg b/.bumpversion.cfg
index df3d3b6..fc03de0 100644
--- a/.bumpversion.cfg
+++ b/.bumpversion.cfg
@@ -1,5 +1,5 @@
 [bumpversion]
-current_version = 0.1.0
+current_version = 0.2.0
 files = setup.py flask_docker.py docs/conf.py
 commit = True
 tag = False
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
new file mode 100644
index 0000000..b0db0ac
--- /dev/null
+++ b/CHANGELOG.rst
@@ -0,0 +1,14 @@
+Changelog
+---------
+
+0.2.0 - 2015-06-08
+~~~~~~~~~~~~~~~~~~
+
+* Make ``app`` attribute always be accessible in :class:`flask_docker.Docker`.
+* Add ``zip_safe=False`` flag to ``setup.py``.
+* Fix some description in the document.
+
+0.1.0 - 2015-02-01
+~~~~~~~~~~~~~~~~~~
+
+* Initial release.
diff --git a/README.rst b/README.rst
index 4b0142b..42a7891 100644
--- a/README.rst
+++ b/README.rst
@@ -3,13 +3,17 @@
 Flask-Docker
 ============
 
-Flask-Docker is an extension for Flask_ that integrates a Docker_ client into
-your application. It is based on the official docker-py_.
+Flask-Docker is an extension for Flask_ that integrates Docker_ client into
+your application. It is based on the official client docker-py_.
 
 .. _Flask: http://flask.pocoo.org
 .. _Docker: https://www.docker.com
 .. _docker-py: https://github.com/docker/docker-py#readme
 
+The document is in ReadTheDocs_.
+
+.. _ReadTheDocs: https://flask-docker.readthedocs.org
+
 
 Installation
 ------------
@@ -40,7 +44,7 @@ You can send a pull reueqst on
 .. |Coverage Status| image:: https://img.shields.io/coveralls/tonyseek/flask-docker.svg?style=flat
    :target: https://coveralls.io/r/tonyseek/flask-docker
    :alt: Coverage Status
-.. |Wheel Status| image:: https://pypip.in/wheel/Flask-Docker/badge.svg?style=flat
+.. |Wheel Status| image:: https://img.shields.io/pypi/wheel/Flask-Docker.svg?style=flat
    :target: https://warehouse.python.org/project/Flask-Docker
    :alt: Wheel Status
 .. |PyPI Version| image:: https://img.shields.io/pypi/v/Flask-Docker.svg?style=flat
diff --git a/docs/conf.py b/docs/conf.py
index 821a154..5ce7ccd 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -55,9 +55,9 @@
 # built documents.
 #
 # The short X.Y version.
-version = '0.1.0'
+version = '0.2.0'
 # The full version, including alpha/beta/rc tags.
-release = '0.1.0'
+release = '0.2.0'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
diff --git a/docs/index.rst b/docs/index.rst
index 9fe9396..c60cc5b 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -19,7 +19,7 @@ Installation
 Configuration
 -------------
 
-You can configure it like mostly extensions of Flask.
+You can configure it like most extensions of Flask.
 
 For single file applications:
 
@@ -52,7 +52,6 @@ For large applications which following the application factory pattern:
 The Flask-Docker has some configuration values that describes how to connect
 to the Docker server.
 
-
 ============================ ==================================================
 `DOCKER_URL`                 The URL of Docker server. **REQUIRED**
 `DOCKER_VERSION`             The API version of Docker server.
@@ -76,8 +75,8 @@ to the Docker server.
                              certificate.
                              Because the client certificate have two files (a
                              public and a private), this configuration value
-                             should be a tuple of their path. (e.g.
-                             ``('/path/to/cert.pem', '/path/to/key.pem')``)
+                             should be a colon-separated tuple of their path.
+                             (e.g. ``"/path/to/cert.pem:/path/to/key.pem"``)
                              This defaults to ``None``.
 `DOCKER_TLS_CA_CERT`         The file path to the CA certificate.
                              It is usually be used with a self-signed
@@ -86,9 +85,8 @@ to the Docker server.
 `DOCKER_TLS_CERT_PATH`       This defaults to ``None``. Once it be specified,
                              The default value of `DOCKER_TLS_CLIENT_CERT` and
                              `DOCKER_TLS_CA_CERT` will be filled to
-                             ``("{DOCKER_TLS_CERT_PATH}/cert.pem",
-                             "{DOCKER_TLS_CERT_PATH}/key.pem")`` and
-                             ``"{DOCKER_TLS_CERT_PATH}/ca.pem"`` instead of
+                             ``"{0}/cert.pem:{0}/key.pem"`` and
+                             ``"{0}/ca.pem"`` instead of
                              ``None``. It is usually be used with boot2docker_.
 ============================ ==================================================
 
@@ -146,3 +144,5 @@ API Reference
 
 .. autoclass:: flask_docker.Docker
    :members:
+
+.. include:: ../CHANGELOG.rst
diff --git a/flask_docker.py b/flask_docker.py
index b62753a..ca2506c 100644
--- a/flask_docker.py
+++ b/flask_docker.py
@@ -6,7 +6,7 @@
 
 
 __all__ = ['Docker']
-__version__ = '0.1.0'
+__version__ = '0.2.0'
 
 
 class Docker(object):
@@ -17,7 +17,9 @@ class Docker(object):
     """
 
     def __init__(self, app=None):
-        if app:
+        if app is None:
+            self.app = current_app
+        else:
             self.app = app
             self.init_app(app)
 
@@ -49,18 +51,16 @@ def client(self):
             docker.create_container('ubuntu')
             docker.client.create_container('ubuntu')  # equivalent
         """
-        app = getattr(self, 'app', current_app)
-
-        if not app.config['DOCKER_URL']:
+        if not self.app.config['DOCKER_URL']:
             raise RuntimeError('"DOCKER_URL" must be specified')
 
-        if not app.extensions['docker.client']:
-            app.extensions['docker.client'] = Client(
-                base_url=app.config['DOCKER_URL'],
-                version=app.config['DOCKER_VERSION'],
-                timeout=app.config['DOCKER_TIMEOUT'],
-                tls=make_tls_config(app.config))
-        return app.extensions['docker.client']
+        if not self.app.extensions['docker.client']:
+            self.app.extensions['docker.client'] = Client(
+                base_url=self.app.config['DOCKER_URL'],
+                version=self.app.config['DOCKER_VERSION'],
+                timeout=self.app.config['DOCKER_TIMEOUT'],
+                tls=make_tls_config(self.app.config))
+        return self.app.extensions['docker.client']
 
     def __getattr__(self, name):
         if name != 'app' and hasattr(self.client, name):
diff --git a/setup.py b/setup.py
index 5ed1f4f..32dd76e 100644
--- a/setup.py
+++ b/setup.py
@@ -9,9 +9,9 @@
 
 setup(
     name='Flask-Docker',
-    description='Uses Docker client in your Flask application.',
+    description='Using Docker client in your Flask application.',
     long_description=long_description,
-    version='0.1.0',
+    version='0.2.0',
     author='Jiangge Zhang',
     author_email='tonyseek@gmail.com',
     url='https://github.com/tonyseek/flask-docker',
@@ -29,9 +29,12 @@
         'Programming Language :: Python :: 3',
         'Programming Language :: Python :: 3.3',
         'Programming Language :: Python :: 3.4',
+        'Programming Language :: Python :: Implementation :: CPython',
+        'Programming Language :: Python :: Implementation :: PyPy',
         'Topic :: Software Development :: Libraries',
         'Topic :: Utilities',
     ],
+    zip_safe=False,
     py_modules=['flask_docker'],
     install_requires=['flask', 'docker-py'],
     platforms=['Any'])
diff --git a/tests/test_factory.py b/tests/test_factory.py
index b59f0da..30f22f2 100644
--- a/tests/test_factory.py
+++ b/tests/test_factory.py
@@ -1,4 +1,4 @@
-from flask import Flask
+from flask import Flask, current_app
 from flask_docker import Docker
 from pytest import fixture, raises
 import responses
@@ -14,7 +14,7 @@ def create_app():
 
 
 @fixture
-def current_app(request):
+def app(request):
     app = create_app()
     ctx = app.app_context()
     ctx.push()
@@ -23,42 +23,49 @@ def current_app(request):
 
 
 def test_factory():
-    assert not hasattr(docker, 'app')
+    assert docker.app is current_app
 
 
 def test_out_of_context():
+    docker.app  # nothing raises
+
+    # but if we...
+    with raises(RuntimeError) as error:
+        docker.app.name
+    assert error.value.args[0] == 'working outside of application context'
+
     with raises(RuntimeError) as error:
         docker.client
     assert error.value.args[0] == 'working outside of application context'
 
 
-def test_url_missing(current_app):
+def test_url_missing(app):
     with raises(RuntimeError) as error:
         docker.client
     assert error.value.args[0] == '"DOCKER_URL" must be specified'
 
 
 @responses.activate
-def test_versioned(current_app):
+def test_versioned(app):
     responses.add(
         responses.GET, 'http://docker-testing:2375/v1.11/info',
         body='{"message": "Yo! Gotcha."}', status=200,
         content_type='application/json')
-    current_app.config['DOCKER_URL'] = 'http://docker-testing:2375'
-    current_app.config['DOCKER_VERSION'] = '1.11'
+    app.config['DOCKER_URL'] = 'http://docker-testing:2375'
+    app.config['DOCKER_VERSION'] = '1.11'
 
     assert docker.client.info() == {'message': 'Yo! Gotcha.'}
 
 
-def test_lazy_creation(current_app):
-    current_app.config['DOCKER_URL'] = 'http://docker-testing:2375'
+def test_lazy_creation(app):
+    app.config['DOCKER_URL'] = 'http://docker-testing:2375'
 
-    assert current_app.extensions['docker.client'] is None
+    assert app.extensions['docker.client'] is None
 
     client1 = docker.client
     client2 = docker.client
 
-    assert current_app.extensions['docker.client'] is client1 is client2
+    assert app.extensions['docker.client'] is client1 is client2
 
 
 def test_isolation():
diff --git a/tests/test_simple.py b/tests/test_simple.py
index 042bdb1..4215276 100644
--- a/tests/test_simple.py
+++ b/tests/test_simple.py
@@ -1,4 +1,4 @@
-from flask import Flask
+from flask import Flask, current_app
 from flask_docker import Docker
 from pytest import fixture, raises
 import responses
@@ -13,6 +13,7 @@ def docker():
 
 def test_singleton(docker):
     assert docker.app
+    assert docker.app is not current_app
 
 
 def test_url_missing(docker):
diff --git a/tox.ini b/tox.ini
index 8d0ab53..44b8b48 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py27,py33,py34,pypy
+envlist = py27,py33,py34,pypy,docs
 [testenv]
 deps =
     setuptools>=12.0
@@ -10,3 +10,11 @@ deps =
     responses
 commands =
     py.test
+[testenv:docs]
+changedir = docs
+deps =
+    --requirement=docs/requirements.txt
+whitelist_externals =
+    make
+commands =
+    make html