Schema setup instructions in README.md are incorrect

[jhodapp]

The instructions in README.md for setting up a new user and granting schema permissions for that new user refactor_rs don't give the right permissions needed to successfully perform the up migration.

The failed run looks like:

DATABASE_URL=postgres://refactor_rs:password@localhost:5432/refactor_platform_rs sea-orm-cli migrate up -s refactor_platform_rs
Running `cargo run --manifest-path ./migration/Cargo.toml -- up -u postgres://refactor_rs:password@localhost:5432/refactor_platform_rs -s refactor_platform_rs`
    Finished dev [unoptimized + debuginfo] target(s) in 0.21s
     Running `target/debug/migration up -u 'postgres://refactor_rs:password@localhost:5432/refactor_platform_rs' -s refactor_platform_rs`
Execution Error: error returned from database: no schema has been selected to create in
Fail to run migration