Refactor project resource to follow expand/flatten pattern (#50)

In addition to following the expand/flatten pattern described here:
    https://terraform.io/docs/extend/writing-custom-providers.html#implementing-a-more-complex-read

This change does the following:
 - Refactor common code into shared package
 - Remove `project_id` property in favor of using the computed `id`

1 files changed, 1 insertions, 1 deletions

diff --git a/README.md b/README.md
index e4d88319..986912c4 100644
--- a/README.md
+++ b/README.md
@@ -38,7 +38,7 @@ resource "azuredevops_project" "project" {
 }
 
 resource "azuredevops_pipeline" "pipeline" {
-  project_id    = azuredevops_project.project.project_id
+  project_id    = azuredevops_project.project.id
   pipeline_name = "Test Pipeline"
 
   repository {