Update Makefile + add vis runscript

Makefile

@@ -1,2 +1,8 @@
-shell_plus:
+shell_plus sp:
 	python manage.py shell_plus
+
+migration_visualizer viz:
+	python manage.py runscript visualize
+
+clean:
+	find  . -name 'migration-dep*' -exec rm {} \;

scripts/visualize.py

@@ -0,0 +1,6 @@
+from utils.visualizer import MigrationVisualizer
+
+
+def run():
+    v = MigrationVisualizer(output_format="jpg")
+    print(v)

utils/visualizer.py

@@ -118,7 +118,7 @@ def build_graph(self):
 
 
 class MigrationVisualizer:
-    def __init__(self, *apps, **options):
+    def __init__(self, *apps, output_format=None, **options):
         self._censor_cache = {}
         self._censor_enabled = bool(options.get("censor", False))
         if self._censor_enabled:
@@ -130,7 +130,7 @@ def __init__(self, *apps, **options):
             date=options.get("date", datetime.utcnow()),  # TODO: use no connection?
         ).graph
         comment = options.get("comment")
-        self.picture = Digraph(comment=comment)
+        self.picture = Digraph(comment=comment, format=output_format)
         save_loc = options.get("filename", "migration-dep-tree")
         self._render(save_loc)