diff --git a/docs/source/changelog.rst b/docs/source/changelog.rst
index 4e2ea2f7..7cf20d20 100644
--- a/docs/source/changelog.rst
+++ b/docs/source/changelog.rst
@@ -1,4 +1,4 @@
-.. Created by changelog.py at 2021-11-29, command
+.. Created by changelog.py at 2021-11-30, command
    '/Users/giffler/.cache/pre-commit/repor6pnmwlm/py_env-default/bin/changelog docs/source/changes compile --output=docs/source/changelog.rst'
    based on the format of 'https://keepachangelog.com/'
 
@@ -6,7 +6,7 @@
 CHANGELOG
 #########
 
-[Unreleased] - 2021-11-29
+[Unreleased] - 2021-11-30
 =========================
 
 Changed
@@ -14,6 +14,11 @@ Changed
 
 * SSHExecutor respects the remote MaxSessions via queueing
 
+Fixed
+-----
+
+* Unique constraints in database schema have been fixed concerning to allow same machine_type and remote_resource_uuid on multiple sites
+
 [0.6.0] - 2021-08-09
 ====================
 
diff --git a/docs/source/changes/220.fix_unique_constraints_db_schema.yaml b/docs/source/changes/220.fix_unique_constraints_db_schema.yaml
new file mode 100644
index 00000000..a53ad71c
--- /dev/null
+++ b/docs/source/changes/220.fix_unique_constraints_db_schema.yaml
@@ -0,0 +1,9 @@
+category: fixed
+summary: "Unique constraints in database schema have been fixed concerning to allow same machine_type and remote_resource_uuid on multiple sites"
+description: |
+  The unique constraints in the datebase schema have been relaxed to allow the same machine_type and the same
+  remote_resource_uuid to be used on multiple sites. In addition, the unittest of the SqliteRegistry have been improved.
+pull_requests:
+  - 220
+issues:
+  - 219