Adding mock for future unit testing

requirements.txt

@@ -17,6 +17,7 @@ ipython==5.5.0
 ligo-lvalert==1.4.3
 ligo-lvalert-overseer==0.1.2
 lxml==4.2.0
+mock==2.0.0
 mysql-python==1.2.5
 packaging==17.1
 phonenumbers==8.8.11