Update readme for setting PGPASSWORD when unable to include password …

…in UTA_DB_URL (#635)

* Allow UTA db to connect via generated aws auth token

* Add boto3 to optional dependencies

* refactor: db password can be set by PG_PASSWORD env var if url.password is empty

* revert styling back to original

* Remove setting env var, update readme

README.rst

@@ -92,11 +92,17 @@ Configuration
 
 `hgvs` will use publicly available data sources unless directed
 otherwise through environment variables, like so::
-  
+
   # N.B. These are examples. The correct values will depend on your installation
   $ export UTA_DB_URL=postgresql://anonymous:anonymous@localhost:5432/uta/uta_20180821
   $ export HGVS_SEQREPO_DIR=/usr/local/share/seqrepo/latest
 
+Alternatively, if you are unable to pass the postgresql password in the
+UTA_DB_URL environment variable (i.e., generating an auth token), you can set
+UTA_DB_URL to ``postgresql://<user>@<host>/<db>/<schema>`` and set PGPASSWORD. For example::
+
+  $ export UTA_DB_URL=postgresql://anonymous@localhost:5432/uta/uta_20180821 PGPASSWORD=anonymous
+
 See the installation instructions for details.