Implement 'user set' command in cli.py.

cli.py

@@ -63,6 +63,26 @@ def user_list():
         print("No users found.")
 
 
+@user.command('set')
+@click.option('-p', '--password')
+@click.argument('user_uid', type=click.INT)
+def user_set(user_uid, password):
+    with db.get_session() as session:
+        user = session.query(User).get(user_uid)
+
+    if not user:
+        print("No user found with id #{}.".format(user_uid))
+        return
+
+    if password:
+        user.password = password
+
+    with db.get_session() as session:
+        session.add(user)
+
+    print("User successfully edited.")
+
+
 @cli.group('event')
 def event():
     pass