added getting started section

Author: benlower

README.md

@@ -1,6 +1,6 @@
 # tableausdk-python
 
-Tableau SDK for Python. Currently this contains only the Document API. This will evolve. Help us by submitting feedback, issues, and pull requests!
+Tableau SDK for Python. Currently this contains only the Document API. We are just getting started and this will evolve. Help us by submitting feedback, issues, and pull requests!
 
 Document API
 ---------------
@@ -13,3 +13,11 @@ Currently only the following operations are supported:
 * Modify database server
 * Modify database name
 * Modify database user
+
+We don't yet support creating files from scratch. Support for .twbx and .tdsx is coming.
+
+##### Getting Started
+We will put this in PyPi to make installation easier. In the meantime, install the package locally with:
+```python
+pip install -e <directory containing setup.py>
+```