Added link to working tarballs of ImageMagick

README.md

@@ -11,6 +11,7 @@
   * Postgres (or other database, though using another database requires changing code). Set port to 5432 (or change code to reflect chosen port). (Setup information: [here](https://help.ubuntu.com/community/PostgreSQL))
   * psycopg2 (required for Postgres)
   * ImageMagick (`ImageMagick 6.7.7-10 Q16` and `ImageMagick-6.9.4 Q16` are known to be working and compatible versions)
+  (Tarball for previous versions can be found [here](https://www.imagemagick.org/download/releases/))
 2. Clone this repo (and navigate to it).
 3. Create a (Postgres) database called `agdss` which has a user `aguser` with a password `aguser` (with all permissions). To change these configurations, see `DATABASE` in aguser/settings.py. The easiest way to do this is through a GUI manager like pgadmin3. However, it can be done via the Unix terminal.
   * If on Windows, one may be required to create a Firewall inbound rule allowing traffic on port 5432 as it is closed by default. This may not be necessary, but attempt if there is a problem.