fix(scheduler): update instead of appending env vars so hardcoded val…

…ues can be overwritten

An example of this would be a user wanting to overwrite a hardcoded PORT or one of the other values Deis may set. Generally people should not do that, however the flexibility should be there in case they want to play with fire

Fixes #766

rootfs/scheduler/__init__.py

@@ -664,7 +664,7 @@ def _set_container(self, namespace, data, **kwargs):  # noqa
                 self._create_secret(namespace, secret_name, secrets_env, labels=labels)
 
             for key in env.keys():
-                data["env"].append({
+                item = {
                     "name": key,
                     "valueFrom": {
                         "secretKeyRef": {
@@ -673,7 +673,14 @@ def _set_container(self, namespace, data, **kwargs):  # noqa
                             "key": key.lower().replace('_', '-')
                         }
                     }
-                })
+                }
+
+                # add value to env hash. Overwrite hardcoded values if need be
+                match = next((k for k, e in enumerate(data["env"]) if e['name'] == key), None)
+                if match is not None:
+                    data["env"][match] = item
+                else:
+                    data["env"].append(item)
 
         # Inject debugging if workflow is in debug mode
         if os.environ.get("DEIS_DEBUG", False):