add decouple to config the system

.gitignore

@@ -113,3 +113,6 @@ ENV/
 .vscode/
 .DS_Store
 /app.py
+
+# Environment
+.env

README.rst

@@ -37,6 +37,11 @@ Create a PostgreSQL database called *devicehub* by running
 -  In MacOS: ``bash examples/create-db.sh devicehub dhub``, and password
    ``ereuse``.
 
+Configure project using environment file (you can use provided example as quickstart):                    
+.. code:: bash 
+   
+   $ cp examples/env.example .env
+
 Using the `dh` tool for set up with one or multiple inventories.
 Create the tables in the database by executing:
 

ereuse_devicehub/config.py

@@ -1,6 +1,7 @@
 from distutils.version import StrictVersion
 from itertools import chain
 from typing import Set
+from decouple import config
 
 from teal.auth import TokenAuth
 from teal.config import Config
@@ -29,7 +30,16 @@ class DevicehubConfig(Config):
                                      import_resource(versions)),
                                )
     PASSWORD_SCHEMES = {'pbkdf2_sha256'}  # type: Set[str]
-    SQLALCHEMY_DATABASE_URI = 'postgresql://dhub:ereuse@localhost/devicehub'  # type: str
+    DB_USER = config('DB_USER', 'dhub')
+    DB_PASSWORD = config('DB_PASSWORD', 'ereuse')
+    DB_HOST = config('DB_HOST', 'localhost')
+    DB_DATABASE = config('DB_DATABASE', 'devicehub')
+    SQLALCHEMY_DATABASE_URI = 'postgresql://{user}:{pw}@{host}/{db}'.format(
+        user=DB_USER,
+        pw=DB_PASSWORD,
+        host=DB_HOST,
+        db=DB_DATABASE,
+    )  # type: str
     MIN_WORKBENCH = StrictVersion('11.0a1')  # type: StrictVersion
     """The minimum version of ereuse.org workbench that this devicehub
     accepts. we recommend not changing this value.

examples/env.example

@@ -0,0 +1,4 @@
+DB_USER='dhub'
+DB_PASSWORD='ereuse'
+DB_HOST='localhost'
+DB_DATABASE='devicehub'

requirements.txt

@@ -34,3 +34,5 @@ weasyprint==44
 psycopg2-binary==2.8.3
 sortedcontainers==2.1.0
 tqdm==4.32.2
+python-decouple==3.3
+python-dotenv==0.14.0