config user db and user session

rust-lib/flowy-sqlite/src/errors.rs

@@ -0,0 +1,22 @@
+use error_chain::{
+    error_chain,
+    error_chain_processing,
+    impl_error_chain_kind,
+    impl_error_chain_processed,
+    impl_extract_backtrace,
+};
+
+error_chain! {
+    errors {
+        UnknownMigrationExists(v: String) {
+             display("unknown migration version: '{}'", v),
+        }
+    }
+    foreign_links {
+        R2D2(::r2d2::Error);
+        Migrations(::diesel_migrations::RunMigrationsError);
+        Diesel(::diesel::result::Error);
+        Connection(::diesel::ConnectionError);
+        Io(::std::io::Error);
+    }
+}