Initial template for registration service

internal/repository/migrations/sqlite3/13_add-service-table.up.sql

@@ -0,0 +1,20 @@
+CREATE TABLE "service" (
+    id INTEGER PRIMARY KEY,
+    cluster VARCHAR(255) NOT NULL,
+    hostname VARCHAR(255) NOT NULL,
+    service_type VARCHAR(255) NOT NULL,
+    instance_id VARCHAR(64) NOT NULL,
+    state VARCHAR(32) NOT NULL DEFAULT 'pending'
+        CHECK (state IN ('pending', 'active', 'stale', 'deregistered')),
+    registered_at INTEGER NOT NULL,
+    last_heartbeat INTEGER,
+    config_revision INTEGER NOT NULL DEFAULT 0,
+    meta_data TEXT,          -- JSON
+    UNIQUE (cluster, hostname, service_type),
+    UNIQUE (instance_id)
+);
+
+CREATE INDEX IF NOT EXISTS services_cluster ON service (cluster);
+CREATE INDEX IF NOT EXISTS services_state_heartbeat ON service (state, last_heartbeat);
+
+PRAGMA optimize;