mysql error when renaming a manyToOne property

These are my initial properties with annotations:

// Task.php
/**

• @ManyToOne(targetEntity="Maia\Model\User", inversedBy="tasks")
  */
  protected $user;

// User.php
/**

• @OneToMany(targetEntity="Maia\Model\Task", mappedBy="user")
  */
  protected $tasks;

At this stage, everythings works fine.

However when I try to rename the property $user to $author like so:

// User.php
/**

• @OneToMany(targetEntity="Maia\Model\Task", mappedBy="author")
  */
  protected $tasks;

and change the corresponding entity like this:
/**

• @ManyToOne(targetEntity="Maia\Model\User", inversedBy="tasks")
  */
  protected $author;

and then try to update my database using the './doctrine orm:schema-tool:update --force' command, I get the following error:
[PDOException]
SQLSTATE[HY000]: General error: 1025 Error on rename of './maia/#sql-508_2be' to './maia/Task' (errno: 150)

in the database 'information_schema' and then tabel 'key_column_usage' I find this line:
CONSTRAINT_CATALOG Null
CONSTRAINT_SCHEMA maia
CONSTRAINT_NAME Task_ibfk_1
TABLE_CATALOG Null
TABLE_SCHEMA maia
TABLE_NAME Task
COLUMN_NAME user_id
ORDINAL_POSITION 1
POSITION_IN_UNIQUE_CONSTRAINT 1
REFERENCED_TABLE_SCHEMA maia
REFERENCED_TABLE_NAME User
REFERENCED_COLUMN_NAME id

I had to perform the following query on my database before I was able to update:
ALTER TABLE User DROP FOREIGN KEY Task_ibfk_1;

Maybe I am doing something wrong, this is my first project with Doctrine, but I tweeted about the error and somebody asked me to create a ticket so here it is.