pull API credentials from env vars (#7)

Author: cesarferradas

README.md

@@ -45,6 +45,9 @@ heron.basic_auth_password = os.getenv("HERON_PASSWORD")
 heron.provider = "plaid"
 ```
 
+Alternatively, set `HERON_USERNAME` and `HERON_PASSWORD` as environment
+variables which will be automatically picked up.
+
 Then you can issue API requests using Python classes:
 
 ```python

heron/__init__.py

@@ -1,7 +1,9 @@
+import os
+
 _base_url = "https://app.herondata.io/api"
 
-basic_auth_username = None
-basic_auth_password = None
+basic_auth_username = os.getenv("HERON_USERNAME")
+basic_auth_password = os.getenv("HERON_PASSWORD")
 provider = None
 
 from .category import Category  # noqa

setup.py

@@ -14,7 +14,7 @@
 # This call to setup() does all the work
 setup(
     name="heron-data",
-    version="0.1.0",
+    version="0.1.1",
     description="A client for the Heron Data API",
     long_description=README,
     long_description_content_type="text/markdown",