added functionality to archive clients

schema.sql

@@ -32,6 +32,8 @@ CREATE TABLE IF NOT EXISTS coach (
 CREATE TABLE IF NOT EXISTS client (
     clientCode TEXT NOT NULL PRIMARY KEY,
     coachID    TEXT NOT NULL,
+    archived   INTEGER NOT NULL DEFAULT 0,
+    archivedAt INTEGER NOT NULL DEFAULT 0,
     FOREIGN KEY(coachID) REFERENCES coach(coachID)
 );