operator key for session json schemas

raml/schemas/definitions/session.json

 {
     "$schema": "http://json-schema.org/draft-04/schema#",
     "definitions":{
+        "operator":     {"type": "string"},
         "project":      {"type": "string"},
         "project_has_template":{"type":"boolean"},
         "satisfies_template":{"type":"boolean"},
         "session-input":{
             "type": "object",
             "properties": {
-                "public": {"$ref": "../definitions/container.json#/definitions/public"},
-                "label": {"$ref": "../definitions/container.json#/definitions/label"},
-                "info": {"$ref": "../definitions/container.json#/definitions/info"},
+                "operator":     {"$ref": "#/definitions/operator"},
+                "public":       {"$ref": "../definitions/container.json#/definitions/public"},
+                "label":        {"$ref": "../definitions/container.json#/definitions/label"},
+                "info":         {"$ref": "../definitions/container.json#/definitions/info"},
                 "archived":     {"$ref":"../definitions/container.json#/definitions/archived"},
                 "project":      {"$ref":"#/definitions/project"},
                 "uid":          {"$ref":"../definitions/container.json#/definitions/uid"},
@@ -24,11 +26,12 @@
         "session-output":{
             "type": "object",
             "properties": {
-                "_id": {"$ref":"../definitions/objectid.json#"},
-                "public": {"$ref": "../definitions/container.json#/definitions/public"},
-                "label": {"$ref": "../definitions/container.json#/definitions/label"},
-                "info": {"$ref": "../definitions/container.json#/definitions/info"},
+                "_id":          {"$ref":"../definitions/objectid.json#"},
+                "public":       {"$ref": "../definitions/container.json#/definitions/public"},
+                "label":        {"$ref": "../definitions/container.json#/definitions/label"},
+                "info":         {"$ref": "../definitions/container.json#/definitions/info"},
                 "archived":     {"$ref":"../definitions/container.json#/definitions/archived"},
+                "operator":     {"$ref": "#/definitions/operator"},
                 "project":      {"$ref":"#/definitions/project"},
                 "uid":          {"$ref":"../definitions/container.json#/definitions/uid"},
                 "timestamp":    {"$ref":"../definitions/container.json#/definitions/timestamp"},

raml/schemas/mongo/session.json

@@ -16,7 +16,7 @@
         "project_has_template": {"type": "boolean"},
         "tags": {},
         "info": {},
-
+        "operator": {},
         "group":        {"type": "string"},
         "project":      {},
         "uid":          {"type": "string"},

tests/integration_tests/python/test_containers.py

@@ -393,6 +393,18 @@ def test_post_container(data_builder, as_admin, as_user):
     })
     assert r.ok
 
+    # create a session w/ operator
+    r = as_user.post('/sessions', json={
+        'project': project,
+        'label': 'test-timestamp-session',
+        'operator': 'Operator'
+    })
+    assert r.ok
+    session = r.json()['_id']
+    r = as_user.get('/sessions/' + session)
+    assert r.ok
+    assert r.json()['operator'] == "Operator"
+
     data_builder.delete_group(group, recursive=True)