Server crashes if text field is too long

Specifically this is a sensor with a unit name that's more than 30 characters, but I'm guessing the issue is in other DB inserts as well.
Traceback (most recent call last):

  File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py", line 114, in get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)

  File "/usr/local/lib/python2.7/dist-packages/django/views/decorators/csrf.py", line 57, in wrapped_view
    return view_func(*args, **kwargs)

  File "/home/sfr/chain-api/chain/core/api.py", line 748, in create_view
    return cls.create_single(data, request)

  File "/home/sfr/chain-api/chain/core/resources.py", line 630, in create_single
    return ScalarSensorResource.create_single(data, req)

  File "/home/sfr/chain-api/chain/core/api.py", line 755, in create_single
    new_resource.save()

  File "/home/sfr/chain-api/chain/core/api.py", line 544, in save
    self.deserialize()

  File "/home/sfr/chain-api/chain/core/api.py", line 500, in deserialize
    new_obj_data, stub_field_name, self._data[stub_field_name])

  File "/home/sfr/chain-api/chain/core/api.py", line 448, in stub_object_finding
    matching_related_obj.save()

  File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", line 545, in save
    force_update=force_update, update_fields=update_fields)

  File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", line 573, in save_base
    updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)

  File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", line 654, in _save_table
    result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)

  File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", line 687, in _do_insert
    using=using, raw=raw)

  File "/usr/local/lib/python2.7/dist-packages/django/db/models/manager.py", line 232, in _insert
    return insert_query(self.model, objs, fields, **kwargs)

  File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 1511, in insert_query
    return query.get_compiler(using=using).execute_sql(return_id)

  File "/usr/local/lib/python2.7/dist-packages/django/db/models/sql/compiler.py", line 899, in execute_sql
    cursor.execute(sql, params)

  File "/usr/local/lib/python2.7/dist-packages/django/db/backends/util.py", line 53, in execute
    return self.cursor.execute(sql, params)

  File "/usr/local/lib/python2.7/dist-packages/django/db/utils.py", line 99, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)

  File "/usr/local/lib/python2.7/dist-packages/django/db/backends/util.py", line 53, in execute
    return self.cursor.execute(sql, params)

DataError: value too long for type character varying(30)

<WSGIRequest
path:/sensors/create,
GET:<QueryDict: {u'device_id': [u'22323']}>,
POST:<QueryDict: {}>,
COOKIES:{},
META:{'CONTENT_LENGTH': '82',
 u'CSRF_COOKIE': u'wxGbCbZIie997Edr4CdwYCaXTIHmyZqw',
 'HTTP_ACCEPT': '*/*',
 'HTTP_ACCEPT_ENCODING': 'gzip, deflate',
 'HTTP_AUTHORIZATION': 'Basic Y2hhaW5jb2xsZWN0b3JzOlY4VGlPRTZ5VndwaklpbTEzeWJoakE5Tw==',
 'HTTP_CONNECTION': 'close',
 'HTTP_HOST': 'chain-api.media.mit.edu',
 'HTTP_USER_AGENT': 'python-requests/2.3.0 CPython/2.7.3 Linux/3.11.0-26-generic',
 'HTTP_X_FORWARDED_FOR': '18.85.58.252',
 'PATH_INFO': u'/sensors/create',
 'QUERY_STRING': 'device_id=22323',
 'RAW_URI': '/sensors/create?device_id=22323',
 'REMOTE_ADDR': '18.85.58.252',
 'REMOTE_PORT': '80',
 'REQUEST_METHOD': 'POST',
 'SCRIPT_NAME': u'',
 'SERVER_NAME': 'chain-api.media.mit.edu',
 'SERVER_PORT': '80',
 'SERVER_PROTOCOL': 'HTTP/1.0',
 'SERVER_SOFTWARE': 'gunicorn/18.0',
 'gunicorn.socket': <socket._socketobject object at 0x2c07a60>,
 'wsgi.errors': <open file '<stderr>', mode 'w' at 0x7fd794eae270>,
 'wsgi.file_wrapper': <class gunicorn.http.wsgi.FileWrapper at 0x1962668>,
 'wsgi.input': <gunicorn.http.body.Body object at 0x2b2f390>,
 'wsgi.multiprocess': True,
 'wsgi.multithread': False,
 'wsgi.run_once': False,
 'wsgi.url_scheme': 'http',
 'wsgi.version': (1, 0)}>
ResEnv / chain-api

Server crashes if text field is too long #60
