Add Organisations endpoints

As part of this we also needed to add:
- schemas for validation
- serialize method for Organisation model

app/organisation/organisation_schema.py

@@ -0,0 +1,21 @@
+post_create_organisation_schema = {
+    "$schema": "http://json-schema.org/draft-04/schema#",
+    "description": "POST organisation schema",
+    "type": "object",
+    "properties": {
+        "name": {"type": "string"},
+        "active": {"type": ["boolean", "null"]}
+    },
+    "required": ["name"]
+}
+
+post_update_organisation_schema = {
+    "$schema": "http://json-schema.org/draft-04/schema#",
+    "description": "POST organisation schema",
+    "type": "object",
+    "properties": {
+        "name": {"type": ["string", "null"]},
+        "active": {"type": ["boolean", "null"]}
+    },
+    "required": []
+}