diff --git a/.sqlx/query-06f83a51e9d2ca842dc0d6947ad39d9be966636700de58d404d8e1471a260c9a.json b/.sqlx/query-06f83a51e9d2ca842dc0d6947ad39d9be966636700de58d404d8e1471a260c9a.json
new file mode 100644
index 0000000..c63606e
--- /dev/null
+++ b/.sqlx/query-06f83a51e9d2ca842dc0d6947ad39d9be966636700de58d404d8e1471a260c9a.json
@@ -0,0 +1,26 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "\n        SELECT newsletter_issue_id, subscriber_email\n        FROM issue_delivery_queue\n        FOR UPDATE\n        SKIP LOCKED\n        LIMIT 1\n        ",
+  "describe": {
+    "columns": [
+      {
+        "ordinal": 0,
+        "name": "newsletter_issue_id",
+        "type_info": "Uuid"
+      },
+      {
+        "ordinal": 1,
+        "name": "subscriber_email",
+        "type_info": "Text"
+      }
+    ],
+    "parameters": {
+      "Left": []
+    },
+    "nullable": [
+      false,
+      false
+    ]
+  },
+  "hash": "06f83a51e9d2ca842dc0d6947ad39d9be966636700de58d404d8e1471a260c9a"
+}
diff --git a/.sqlx/query-0b93f6f4f1bc59e7ee597ef6df52bbee1233d98e0a4cf53e29c153ccdae0537b.json b/.sqlx/query-0b93f6f4f1bc59e7ee597ef6df52bbee1233d98e0a4cf53e29c153ccdae0537b.json
new file mode 100644
index 0000000..9027d6f
--- /dev/null
+++ b/.sqlx/query-0b93f6f4f1bc59e7ee597ef6df52bbee1233d98e0a4cf53e29c153ccdae0537b.json
@@ -0,0 +1,17 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "\n        INSERT INTO newsletter_issues (\n            newsletter_issue_id, \n            title, \n            text_content, \n            html_content,\n            published_at\n        )\n        VALUES ($1, $2, $3, $4, now())\n        ",
+  "describe": {
+    "columns": [],
+    "parameters": {
+      "Left": [
+        "Uuid",
+        "Text",
+        "Text",
+        "Text"
+      ]
+    },
+    "nullable": []
+  },
+  "hash": "0b93f6f4f1bc59e7ee597ef6df52bbee1233d98e0a4cf53e29c153ccdae0537b"
+}
diff --git a/.sqlx/query-1bb5d1c15161a276262535134c306bc392dda0fa1d7bb7deddcd544583a19fc8.json b/.sqlx/query-1bb5d1c15161a276262535134c306bc392dda0fa1d7bb7deddcd544583a19fc8.json
new file mode 100644
index 0000000..c8bb147
--- /dev/null
+++ b/.sqlx/query-1bb5d1c15161a276262535134c306bc392dda0fa1d7bb7deddcd544583a19fc8.json
@@ -0,0 +1,15 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "\n        INSERT INTO idempotency (\n            user_id, \n            idempotency_key,\n            created_at\n        ) \n        VALUES ($1, $2, now()) \n        ON CONFLICT DO NOTHING\n        ",
+  "describe": {
+    "columns": [],
+    "parameters": {
+      "Left": [
+        "Uuid",
+        "Text"
+      ]
+    },
+    "nullable": []
+  },
+  "hash": "1bb5d1c15161a276262535134c306bc392dda0fa1d7bb7deddcd544583a19fc8"
+}
diff --git a/.sqlx/query-21f0f4c2ae0e88b99684823b83ce6126c218cec3badc8126492aab8fc7042109.json b/.sqlx/query-21f0f4c2ae0e88b99684823b83ce6126c218cec3badc8126492aab8fc7042109.json
new file mode 100644
index 0000000..04944e8
--- /dev/null
+++ b/.sqlx/query-21f0f4c2ae0e88b99684823b83ce6126c218cec3badc8126492aab8fc7042109.json
@@ -0,0 +1,41 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "\n        UPDATE idempotency\n        SET \n            response_status_code = $3, \n            response_headers = $4,\n            response_body = $5\n        WHERE\n            user_id = $1 AND\n            idempotency_key = $2\n        ",
+  "describe": {
+    "columns": [],
+    "parameters": {
+      "Left": [
+        "Uuid",
+        "Text",
+        "Int2",
+        {
+          "Custom": {
+            "name": "_header_pair",
+            "kind": {
+              "Array": {
+                "Custom": {
+                  "name": "header_pair",
+                  "kind": {
+                    "Composite": [
+                      [
+                        "name",
+                        "Text"
+                      ],
+                      [
+                        "value",
+                        "Bytea"
+                      ]
+                    ]
+                  }
+                }
+              }
+            }
+          }
+        },
+        "Bytea"
+      ]
+    },
+    "nullable": []
+  },
+  "hash": "21f0f4c2ae0e88b99684823b83ce6126c218cec3badc8126492aab8fc7042109"
+}
diff --git a/.sqlx/query-38d1a12165ad4f50d8fbd4fc92376d9cc243dcc344c67b37f7fef13c6589e1eb.json b/.sqlx/query-38d1a12165ad4f50d8fbd4fc92376d9cc243dcc344c67b37f7fef13c6589e1eb.json
new file mode 100644
index 0000000..f1fd51c
--- /dev/null
+++ b/.sqlx/query-38d1a12165ad4f50d8fbd4fc92376d9cc243dcc344c67b37f7fef13c6589e1eb.json
@@ -0,0 +1,34 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "\n        SELECT title, text_content, html_content\n        FROM newsletter_issues\n        WHERE\n            newsletter_issue_id = $1\n        ",
+  "describe": {
+    "columns": [
+      {
+        "ordinal": 0,
+        "name": "title",
+        "type_info": "Text"
+      },
+      {
+        "ordinal": 1,
+        "name": "text_content",
+        "type_info": "Text"
+      },
+      {
+        "ordinal": 2,
+        "name": "html_content",
+        "type_info": "Text"
+      }
+    ],
+    "parameters": {
+      "Left": [
+        "Uuid"
+      ]
+    },
+    "nullable": [
+      false,
+      false,
+      false
+    ]
+  },
+  "hash": "38d1a12165ad4f50d8fbd4fc92376d9cc243dcc344c67b37f7fef13c6589e1eb"
+}
diff --git a/.sqlx/query-7b57e2776a245ba1602f638121550485e2219a6ccaaa62b5ec3e4683e33a3b5f.json b/.sqlx/query-7b57e2776a245ba1602f638121550485e2219a6ccaaa62b5ec3e4683e33a3b5f.json
deleted file mode 100644
index 456b739..0000000
--- a/.sqlx/query-7b57e2776a245ba1602f638121550485e2219a6ccaaa62b5ec3e4683e33a3b5f.json
+++ /dev/null
@@ -1,20 +0,0 @@
-{
-  "db_name": "PostgreSQL",
-  "query": "\n        SELECT email\n        FROM subscriptions\n        WHERE status = 'confirmed'\n        ",
-  "describe": {
-    "columns": [
-      {
-        "ordinal": 0,
-        "name": "email",
-        "type_info": "Text"
-      }
-    ],
-    "parameters": {
-      "Left": []
-    },
-    "nullable": [
-      false
-    ]
-  },
-  "hash": "7b57e2776a245ba1602f638121550485e2219a6ccaaa62b5ec3e4683e33a3b5f"
-}
diff --git a/.sqlx/query-9f103f7d6dfa569bafce4546e6e610f3d31b95fe81f96ea72575b27ddfea796e.json b/.sqlx/query-9f103f7d6dfa569bafce4546e6e610f3d31b95fe81f96ea72575b27ddfea796e.json
new file mode 100644
index 0000000..00509f8
--- /dev/null
+++ b/.sqlx/query-9f103f7d6dfa569bafce4546e6e610f3d31b95fe81f96ea72575b27ddfea796e.json
@@ -0,0 +1,58 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "\n        SELECT \n            response_status_code as \"response_status_code!\", \n            response_headers as \"response_headers!: Vec<HeaderPairRecord>\",\n            response_body as \"response_body!\"\n        FROM idempotency\n        WHERE \n          user_id = $1 AND\n          idempotency_key = $2\n        ",
+  "describe": {
+    "columns": [
+      {
+        "ordinal": 0,
+        "name": "response_status_code!",
+        "type_info": "Int2"
+      },
+      {
+        "ordinal": 1,
+        "name": "response_headers!: Vec<HeaderPairRecord>",
+        "type_info": {
+          "Custom": {
+            "name": "_header_pair",
+            "kind": {
+              "Array": {
+                "Custom": {
+                  "name": "header_pair",
+                  "kind": {
+                    "Composite": [
+                      [
+                        "name",
+                        "Text"
+                      ],
+                      [
+                        "value",
+                        "Bytea"
+                      ]
+                    ]
+                  }
+                }
+              }
+            }
+          }
+        }
+      },
+      {
+        "ordinal": 2,
+        "name": "response_body!",
+        "type_info": "Bytea"
+      }
+    ],
+    "parameters": {
+      "Left": [
+        "Uuid",
+        "Text"
+      ]
+    },
+    "nullable": [
+      true,
+      true,
+      true
+    ]
+  },
+  "hash": "9f103f7d6dfa569bafce4546e6e610f3d31b95fe81f96ea72575b27ddfea796e"
+}
diff --git a/.sqlx/query-aa682ff5c6485c4faa8168322413294a282ddcc0ef4e38ca3980e6fc7c00c87c.json b/.sqlx/query-aa682ff5c6485c4faa8168322413294a282ddcc0ef4e38ca3980e6fc7c00c87c.json
new file mode 100644
index 0000000..7e9a9b9
--- /dev/null
+++ b/.sqlx/query-aa682ff5c6485c4faa8168322413294a282ddcc0ef4e38ca3980e6fc7c00c87c.json
@@ -0,0 +1,14 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "\n        INSERT INTO issue_delivery_queue (\n            newsletter_issue_id, \n            subscriber_email\n        )\n        SELECT $1, email\n        FROM subscriptions\n        WHERE status = 'confirmed'\n        ",
+  "describe": {
+    "columns": [],
+    "parameters": {
+      "Left": [
+        "Uuid"
+      ]
+    },
+    "nullable": []
+  },
+  "hash": "aa682ff5c6485c4faa8168322413294a282ddcc0ef4e38ca3980e6fc7c00c87c"
+}
diff --git a/.sqlx/query-c00b32b331e0444b4bb0cd823b71a8c7ed3a3c8f2b8db3b12c6fbc434aa4d34b.json b/.sqlx/query-c00b32b331e0444b4bb0cd823b71a8c7ed3a3c8f2b8db3b12c6fbc434aa4d34b.json
new file mode 100644
index 0000000..aa5de36
--- /dev/null
+++ b/.sqlx/query-c00b32b331e0444b4bb0cd823b71a8c7ed3a3c8f2b8db3b12c6fbc434aa4d34b.json
@@ -0,0 +1,15 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "\n        DELETE FROM issue_delivery_queue\n        WHERE \n            newsletter_issue_id = $1 AND\n            subscriber_email = $2 \n        ",
+  "describe": {
+    "columns": [],
+    "parameters": {
+      "Left": [
+        "Uuid",
+        "Text"
+      ]
+    },
+    "nullable": []
+  },
+  "hash": "c00b32b331e0444b4bb0cd823b71a8c7ed3a3c8f2b8db3b12c6fbc434aa4d34b"
+}