Non-digit characters in port.

Nobody has claimed this yet.

I get this error when calling

synapse-compress-state -p "postgresql://some-username:localhost/synapse" -r "${room}"

```
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Error(ConnectParams(StringError("Non-digit characters in port.")))', src/libcore/result.rs:997:5
stack backtrace:
0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
1: std::sys_common::backtrace::print
2: std::panicking::default_hook::{{closure}}
3: std::panicking::default_hook
4: std::panicking::rust_panic_with_hook
5: std::panicking::continue_panic_fmt
6: rust_begin_unwind
7: core::panicking::panic_fmt
8: core::result::unwrap_failed
at /usr/src/rustc-1.34.2/src/libcore/macros.rs:17
9: >::unwrap
at /usr/src/rustc-1.34.2/src/libcore/result.rs:798
10: synapse_compress_state::database::get_data_from_db
at src/database.rs:34
11: synapse_compress_state::main
at src/main.rs:185
12: std::rt::lang_start::{{closure}}
at /usr/src/rustc-1.34.2/src/libstd/rt.rs:64
13: std::panicking::try::do_call
14: __rust_maybe_catch_panic
15: std::rt::lang_start_internal
16: std::rt::lang_start
at /usr/src/rustc-1.34.2/src/libstd/rt.rs:64
17: main
18: __libc_start_main
19: _start
```

Reproduce the reported command, then read src/database.rs at line 34 and the call from src/main.rs at line 185. Determine how the PostgreSQL connection error is handled and define completion as the command no longer panicking on this input, with an appropriate reported result.

Written by the indexing model from the issue text.