**Description**

I have noticed that the stable REST API doesn't have the ability to run a task (which is possible from the airflow web interface.
I think it would be nice to have either:
- Run task 
- Run all failing tasks (rerun from point of failure)
this ability for integrations.

**Use case / motivation**

I would like the ability to identify the failing tasks on a specific DAG Run and rerun only them.
I would like to do it remotely (non-interactive) using the REST API.
I could write a script that run only the failing tasks, but I couldn't find a way to "Run" a task, when I have the task instance ID.

**Are you willing to submit a PR?**

Not at this stage

**Related Issues**



airflow/models/dag.py
"""A tag name per dag, to allow quick filtering in the DAG view."""
    __tablename__ = "dag_tag"
    name = Column(String(100), primary_key=True)
    dag_id = Column(String(ID_LEN), ForeignKey('dag.dag_id'), primary_key=True)
    def __repr__(self):
        return self.name
class DagModel(Base):
    """Table containing DAG properties"""
    __tablename__ = "dag"
    """
    These items are stored in the database for state related information
    """
    dag_id = Column(String(ID_LEN), primary_key=True)
    root_dag_id = Column(String(ID_LEN))
    
    
    is_paused_at_creation = conf.getboolean('core', 'dags_are_paused_at_creation')
    is_paused = Column(Boolean, default=is_paused_at_creation)
    
    is_subdag = Column(Boolean, default=False)
    
    is_active = Column(Boolean, default=False)
    
    last_parsed_time = Column(UtcDateTime)
    
    last_pickled = Column(UtcDateTime)
    
    
    last_expired = Column(UtcDateTime)