Add incompatible PG migrations.

Foo

crates/core/src/connection.rs

@@ -313,19 +313,27 @@ struct InitDbOptions<'a> {
 async fn init_db<'a>(
   opts: InitDbOptions<'a>,
 ) -> Result<(Connection, ConnectionMetadata, bool), ConnectionError> {
-  let opts = trailbase_sqlite::generic::PgOptions {
-    host: Some("localhost".to_string()),
+  // TODO: Use `state.pg_uri`.
+  let conn = trailbase_sqlite::Connection::pg_with_opts(trailbase_sqlite::generic::PgOptions {
+    host: Some("127.0.0.1".to_string()),
     port: Some(5432),
     user: Some("postgres".to_string()),
     password: Some("example".to_string()),
     num_threads: Some(2),
+  })?;
+
+  // Apply migrations.
+  //
+  // IMPORTANT: All extensions need to be loaded before to satisfy potential dependencies.
+  let init_schema = if opts.is_main_db {
+    apply_main_migrations(&conn, opts.migration_path)
+      .await
+      .map_err(|err| trailbase_sqlite::Error::Other(err.into()))?
+  } else {
+    false
   };
 
-  let conn = trailbase_sqlite::Connection::pg_with_opts(opts)?;
-
-  // FIXME: Apply migrations.
-
-  return Ok((conn, Default::default(), true));
+  return Ok((conn, Default::default(), init_schema));
 }
 
 #[cfg(not(feature = "pg"))]