Move main.rs to examples/postgres

Cargo.toml

@@ -16,4 +16,7 @@ log = "0.4.7"
 md-5 = "0.8.0"
 memchr = "2.2.1"
 runtime = { version = "=0.3.0-alpha.6", default-features = false }
+
+[dev-dependencies]
 runtime-tokio = { version = "=0.3.0-alpha.5" }
+env_logger = "0.6.2"

examples/postgres.rs

@@ -9,6 +9,8 @@ use std::io;
 
 #[runtime::main(runtime_tokio::Tokio)]
 async fn main() -> io::Result<()> {
+    env_logger::init();
+
     // Connect as postgres / postgres and DROP the sqlx__dev database
     // if exists and then re-create it
     let mut conn = Connection::establish(