Move TESTS section to CONTRIBUTING.md and trim contributors list

Migrate the manual database setup, dependency install, and test
invocation steps from README's TESTS section into CONTRIBUTING.md (under
a new "Manual setup (without devcontainer)" section) and replace the
README section with a pointer. The README's hand-maintained CONTRIBUTORS
list is replaced with a thank-you note plus a link to
github.com/rsim/ruby-plsql/graphs/contributors so the canonical list
lives on GitHub instead of drifting in the repo.

Author: yahonda

CONTRIBUTING.md

@@ -108,3 +108,39 @@ BUNDLE_ONLY=rubocop bundle exec rubocop --parallel
 ```
 
 These are the same commands CI runs (`.github/workflows/rubocop.yml`).
+
+## Manual setup (without devcontainer)
+
+If you prefer to develop against an existing Oracle Database, review
+`spec/spec_helper.rb` for the default schema/user names and database
+names (override via environment variables as needed).
+
+### Prepare the database
+
+Use any reachable Oracle Database and create the test schemas:
+
+```sql
+CREATE USER hr IDENTIFIED BY hr;
+GRANT unlimited tablespace, create session, create table,
+      create sequence, create procedure, create type,
+      create view, create synonym TO hr;
+
+CREATE USER arunit IDENTIFIED BY arunit;
+GRANT create session TO arunit;
+```
+
+The CI helper `ci/setup_accounts.sh` performs the equivalent setup
+against `${DATABASE_NAME}` using `${DATABASE_SYS_PASSWORD}`.
+
+### Prepare dependencies
+
+```sh
+gem install bundler
+bundle install
+```
+
+### Run the suite
+
+```sh
+bundle exec rake spec
+```

README.md

@@ -180,31 +180,7 @@ Make sure you use correct version of Oracle client for database you're connectin
 TESTS
 -----
 
-Review `spec/spec_helper.rb` to see default schema/user names and database names (use environment variables to override defaults)
-
-##### Prepare database
-
-In an Oracle Database create the following schemas for test purposes.
-
-        SQL> CREATE USER hr IDENTIFIED BY hr;
-        SQL> GRANT unlimited tablespace, create session, create table, create sequence, create procedure, create type, create view, create synonym TO hr;
-
-        SQL> CREATE USER arunit IDENTIFIED BY arunit;
-        SQL> GRANT create session TO arunit;
-
-##### Prepare dependencies
-
-* Install bundler with
-
-        gem install bundler
-
-* Install necessary gems with
-
-        bundle install
-
-##### Run tests
-
-        rake spec
+See [CONTRIBUTING.md](CONTRIBUTING.md) for how to set up a development environment and run the spec suite.
 
 LINKS
 -----
@@ -216,13 +192,7 @@ LINKS
 CONTRIBUTORS
 ------------
 
-* Raimonds Simanovskis
-* Edgars Beigarts
-* Oleh Mykytyuk
-* Wiehann Matthysen
-* Dayle Larson
-* Yasuo Honda
-* Yavor Nikolov
+Thanks to everyone who has contributed to ruby-plsql over the years. The up-to-date list is maintained on GitHub: https://github.com/rsim/ruby-plsql/graphs/contributors
 
 LICENSE
 -------