title: Unsuccessful command execution on instance id(s)
body: <p>I am trying to deploy my app on AWS but it seems to stuck at this point:</p>
  
  <pre><code>Uploading: [##################################################] 100% Done...
  2019-10-22 11:01:57    INFO    Environment update is starting.
  2019-10-22 11:02:00    INFO    Deploying new version to instance(s).
  2019-10-22 11:02:09    ERROR   Your requirements.txt is invalid. Snapshot your logs for details.
  2019-10-22 11:02:10    ERROR   [Instance: i-#######] Command failed on instance. Return code: 1 Output: (TRUNCATED)...)
    File "/usr/lib64/python2.7/subprocess.py", line 190, in check_call
      raise CalledProcessError(retcode, cmd)
  CalledProcessError: Command '/opt/python/run/venv/bin/pip install -r /opt/python/ondeck/app/requirements.txt' returned non-zero exit status 1.
  Hook /opt/elasticbeanstalk/hooks/appdeploy/pre/03deploy.py failed. For more detail, check /var/log/eb-activity.log using console or EB CLI.
  2019-10-22 11:02:10    INFO    Command execution completed on all instances. Summary: [Successful: 0, Failed: 1].
  2019-10-22 11:02:10    ERROR   Unsuccessful command execution on instance id(s) 'i########'. Aborting the operation.
  2019-10-22 11:02:11    ERROR   Failed to deploy application.
  
  ERROR: ServiceError - Failed to deploy application.
  </code></pre>
  
  <p>It says that my requirements.txt is invalid, Why ?</p>
  
  <p>Requirement.txt</p>
  
  <pre><code>Django
  django-crispy-forms==1.7.0
  pytz==2017.3
  gunicorn==19.9.0
  django-widget-tweaks
  psycopg2
  </code></pre>
  
  <p>Please help me in figuring out what I am doing wrong.</p>