Add code coverage script

.coveragerc

@@ -0,0 +1,2 @@
+[run]
+source = bookmarks

coverage.sh

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+
+coverage erase
+coverage run manage.py test
+coverage report --sort=cover

requirements.txt

@@ -2,6 +2,7 @@ beautifulsoup4==4.7.1
 certifi==2019.6.16
 chardet==3.0.4
 confusable-homoglyphs==3.2.0
+coverage==5.5
 Django==2.2.20
 django-appconf==1.0.3
 django-compressor==2.3