add BridgeError to error.rs

src/error.rs

@@ -52,6 +52,7 @@ pub enum Error {
     JsonRpcError(String),
     RocksdbError(String),
     TreeFull,
+    BridgeError(String),
     SerdeJsonError(String),
     SurfHttpError(String),
     TomlDeserializeError(String),
@@ -108,6 +109,7 @@ impl fmt::Display for Error {
             Error::RocksdbError(ref err) => write!(f, "Rocksdb Error: {}", err),
             Error::JsonRpcError(ref err) => write!(f, "JsonRpc Error: {}", err),
             Error::TreeFull => f.write_str("MerkleTree is full"),
+            Error::BridgeError(ref err) => write!(f, "Bridge error: {}", err),
             Error::SerdeJsonError(ref err) => write!(f, "Json serialization error: {}", err),
             Error::SurfHttpError(ref err) => write!(f, "Surf Http error: {}", err),
             Error::TomlDeserializeError(ref err) => write!(f, "Toml parsing error: {}", err),