Feature: Added a column called print in bill to the table customer.

This will prevent printing all customer's names and phone numbers in the bill in case of simple walkins.
This is a breaking change as there is schema changes in the database.
It also bolds the customers who are to be printed in the bill in the running tables list.

barker/alembic/versions/e5e8acfc6495_print_customer.py

@@ -0,0 +1,29 @@
+"""print customer
+
+Revision ID: e5e8acfc6495
+Revises: 48bc1c7c07ce
+Create Date: 2021-06-27 09:57:43.034956
+
+"""
+import sqlalchemy as sa
+
+from alembic import op
+
+# revision identifiers, used by Alembic.
+from sqlalchemy.sql import expression
+
+
+revision = "e5e8acfc6495"
+down_revision = "48bc1c7c07ce"
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.add_column(
+        "customers", sa.Column("print_in_bill", sa.Boolean(), nullable=False, server_default=expression.false())
+    )
+
+
+def downgrade():
+    op.drop_column("customers", "print_in_bill")