Allow purchase orders to be completed directly from the app (#686)

* Allow purchase orders to be completed directly from the app

* Code formatting

tasks.py

@@ -5,6 +5,11 @@ import sys
 from invoke import task
 
 
+@task
+def format(c):
+    """Code formatting using dart format."""
+    c.run("fvm dart format lib")
+
 @task
 def clean(c):
     """Clean flutter build."""