message: documenting the `privateKey` behaviour in the `addProject` mutation
diff: @@ -251,6 +251,9 @@ mutation {
  This query adds a new project to be deployed, which is a git repository with a `.lagoon.yml` configuration file committed in the root.
  +If you omit the `privateKey` field a new SSH Key will for the project will be generated automatically. If you would like to reuse a key from another project you
  +will need to supply the key in the `addProject` mutation.
  +
  ```graphql
  mutation {
  addProject(
  