title: Airflow on Docker - Path issue
body: <p>Working with airflow I try simple DAG work.</p>
  
  <p>I wrote custom operators and other files that I want to import into the main file where the DAG logic is.</p>
  
  <p>Here the folder's structure :</p>
  
  <pre><code>├── airflow.cfg
  ├── dags
  │   ├── __init__.py
  │   ├── dag.py
  │   └── sql_statements.sql
  ├── docker-compose.yaml
  ├── environment.yml
  └── plugins
      ├── __init__.py
      └── operators
          ├── __init__.py
          ├── facts_calculator.py
          ├── has_rows.py
          └── s3_to_redshift.py
  
  </code></pre>
  
  <p>I setup the volume right in the <code>compose file</code> since I can see them when I log into the container's terminal.</p>
  
  <p>I followed some tutorials online from where I have added some <code>__init__.py</code>.</p>
  
  <p>The 2 none empty <code>__init__</code> are into </p>
  
  <ul>
  <li><code>/plugins/operators</code>:</li>
  </ul>
  
  <pre><code>from operators.facts_calculator import FactsCalculatorOperator
  from operators.has_rows import HasRowsOperator
  from operators.s3_to_redshift import S3ToRedshiftOperator
  
  __all__ = [
      'FactsCalculatorOperator',
      'HasRowsOperator',
      'S3ToRedshiftOperator'
  ]
  </code></pre>
  
  <ul>
  <li><code>/plugins</code>:</li>
  </ul>
  
  <pre><code>from airflow.plugins_manager import AirflowPlugin
  
  import operators
  
  # Defining the plugin class
  class CustomPlugin(AirflowPlugin):
      name = "custom_plugin"
      # A list of class(es) derived from BaseOperator
      operators = [
          operators.FactsCalculatorOperator,
          operators.HasRowsOperator,
          operators.S3ToRedshiftOperator
      ]
      # A list of class(es) derived from BaseHook
      hooks = []
      # A list of class(es) derived from BaseExecutor
      executors = []
      # A list of references to inject into the macros namespace
      macros = []
      # A list of objects created from a class derived
      # from flask_admin.BaseView
      admin_views = []
      # A list of Blueprint object created from flask.Blueprint
      flask_blueprints = []
      # A list of menu links (flask_admin.base.MenuLink)
      menu_links = []
  </code></pre>
  
  <p>But I keep getting errors from my IDE (saying <code>No module named operators</code> or Unresolved reference operators inside the operator's <code>__init__</code>).</p>
  
  <p>Since everything fails to launch on the webserver.</p>
  
  <p>Any idea how to set this up ? Where I'm wrong ?</p>