chore: add copyright headers

Make sure we obey the REUSE (https://reuse.software) specification and the
origin, copyright owner, and license of all files are clearly marked.

The whole project is under the EPL-2.0, except for trivial files where copyright
is not applicable that are marked with the CC0-1.0 license. Moreover, code
included from third parties is also available under the respective license.

chore: add CONTRIBUTORS.md

List all authors and supporting organizations in accordance with the REUSE
specification.

6 files changed, 30 insertions, 0 deletions

diff --git a/subprojects/language-web/src/test/java/tools/refinery/language/web/ProblemWebSocketServletIntegrationTest.java b/subprojects/language-web/src/test/java/tools/refinery/language/web/ProblemWebSocketServletIntegrationTest.java
index ecbefc4f..53a757eb 100644
--- a/subprojects/language-web/src/test/java/tools/refinery/language/web/ProblemWebSocketServletIntegrationTest.java
+++ b/subprojects/language-web/src/test/java/tools/refinery/language/web/ProblemWebSocketServletIntegrationTest.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.web;
 
 import org.eclipse.jetty.ee10.servlet.ServletContextHandler;
diff --git a/subprojects/language-web/src/test/java/tools/refinery/language/web/tests/AwaitTerminationExecutorServiceProvider.java b/subprojects/language-web/src/test/java/tools/refinery/language/web/tests/AwaitTerminationExecutorServiceProvider.java
index c634e8fc..630549d4 100644
--- a/subprojects/language-web/src/test/java/tools/refinery/language/web/tests/AwaitTerminationExecutorServiceProvider.java
+++ b/subprojects/language-web/src/test/java/tools/refinery/language/web/tests/AwaitTerminationExecutorServiceProvider.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.web.tests;
 
 import com.google.inject.Singleton;
diff --git a/subprojects/language-web/src/test/java/tools/refinery/language/web/tests/ProblemWebInjectorProvider.java b/subprojects/language-web/src/test/java/tools/refinery/language/web/tests/ProblemWebInjectorProvider.java
index 43c12faa..4a5eed95 100644
--- a/subprojects/language-web/src/test/java/tools/refinery/language/web/tests/ProblemWebInjectorProvider.java
+++ b/subprojects/language-web/src/test/java/tools/refinery/language/web/tests/ProblemWebInjectorProvider.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.web.tests;
 
 import org.eclipse.xtext.ide.ExecutorServiceProvider;
diff --git a/subprojects/language-web/src/test/java/tools/refinery/language/web/tests/RestartableCachedThreadPool.java b/subprojects/language-web/src/test/java/tools/refinery/language/web/tests/RestartableCachedThreadPool.java
index cf805eda..09079aa8 100644
--- a/subprojects/language-web/src/test/java/tools/refinery/language/web/tests/RestartableCachedThreadPool.java
+++ b/subprojects/language-web/src/test/java/tools/refinery/language/web/tests/RestartableCachedThreadPool.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.web.tests;
 
 import com.google.inject.Provider;
diff --git a/subprojects/language-web/src/test/java/tools/refinery/language/web/tests/WebSocketIntegrationTestClient.java b/subprojects/language-web/src/test/java/tools/refinery/language/web/tests/WebSocketIntegrationTestClient.java
index f19c10ca..2ac53ea6 100644
--- a/subprojects/language-web/src/test/java/tools/refinery/language/web/tests/WebSocketIntegrationTestClient.java
+++ b/subprojects/language-web/src/test/java/tools/refinery/language/web/tests/WebSocketIntegrationTestClient.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.web.tests;
 
 import org.eclipse.jetty.ee10.websocket.api.Session;
diff --git a/subprojects/language-web/src/test/java/tools/refinery/language/web/xtext/servlet/TransactionExecutorTest.java b/subprojects/language-web/src/test/java/tools/refinery/language/web/xtext/servlet/TransactionExecutorTest.java
index 17f1ff5c..841bacd3 100644
--- a/subprojects/language-web/src/test/java/tools/refinery/language/web/xtext/servlet/TransactionExecutorTest.java
+++ b/subprojects/language-web/src/test/java/tools/refinery/language/web/xtext/servlet/TransactionExecutorTest.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.web.xtext.servlet;
 
 import com.google.inject.Inject;