[WIP] added endpoint and dao to create invites for users.

Droped token as later code to send email invite can generate
timebased url to send to user. That can then be checked
against configurable time threshold for expiry. Therefore
no need to store a token.

app/invite/rest.py

@@ -0,0 +1,24 @@
+from flask import (
+    Blueprint,
+    request,
+    jsonify
+)
+
+from app.dao.invited_user_dao import save_invited_user
+from app.schemas import invited_user_schema
+
+invite = Blueprint('invite', __name__, url_prefix='/service/<service_id>/invite')
+
+from app.errors import register_errors
+register_errors(invite)
+
+
+@invite.route('', methods=['POST'])
+def create_invite_user(service_id):
+    invited_user, errors = invited_user_schema.load(request.get_json())
+    if errors:
+        return jsonify(result="error", message=errors), 400
+
+    save_invited_user(invited_user)
+
+    return jsonify(data=invited_user_schema.dump(invited_user).data), 201