add READMEs to new crates

Author: andygrove

datafusion/expr-common/README.md

@@ -0,0 +1,26 @@
+<!---
+  Licensed to the Apache Software Foundation (ASF) under one
+  or more contributor license agreements.  See the NOTICE file
+  distributed with this work for additional information
+  regarding copyright ownership.  The ASF licenses this file
+  to you under the Apache License, Version 2.0 (the
+  "License"); you may not use this file except in compliance
+  with the License.  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing,
+  software distributed under the License is distributed on an
+  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+  KIND, either express or implied.  See the License for the
+  specific language governing permissions and limitations
+  under the License.
+-->
+
+# DataFusion Logical Plan and Expressions
+
+[DataFusion][df] is an extensible query execution framework, written in Rust, that uses Apache Arrow as its in-memory format.
+
+This crate is a submodule of DataFusion that provides data types and utilities for logical plans and expressions.
+
+[df]: https://crates.io/crates/datafusion

datafusion/functions-aggregate-common/README.md

@@ -0,0 +1,27 @@
+<!---
+  Licensed to the Apache Software Foundation (ASF) under one
+  or more contributor license agreements.  See the NOTICE file
+  distributed with this work for additional information
+  regarding copyright ownership.  The ASF licenses this file
+  to you under the Apache License, Version 2.0 (the
+  "License"); you may not use this file except in compliance
+  with the License.  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing,
+  software distributed under the License is distributed on an
+  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+  KIND, either express or implied.  See the License for the
+  specific language governing permissions and limitations
+  under the License.
+-->
+
+# DataFusion Aggregate Function Library
+
+[DataFusion][df] is an extensible query execution framework, written in Rust, that uses Apache Arrow as its in-memory format.
+
+This crate contains packages of function that can be used to customize the
+functionality of DataFusion.
+
+[df]: https://crates.io/crates/datafusion

dev/release/README.md

@@ -260,18 +260,21 @@ Verify that the Cargo.toml in the tarball contains the correct version
 
 ```shell
 (cd datafusion/common && cargo publish)
+(cd datafusion/expr-common && cargo publish)
+(cd datafusion/physical-expr-common && cargo publish)
+(cd datafusion/functions-aggregate-common && cargo publish)
 (cd datafusion/expr && cargo publish)
 (cd datafusion/execution && cargo publish)
-(cd datafusion/physical-expr-common && cargo publish)
-(cd datafusion/functions-aggregate && cargo publish)
 (cd datafusion/physical-expr && cargo publish)
+(cd datafusion/functions-aggregate && cargo publish)
 (cd datafusion/functions && cargo publish)
 (cd datafusion/functions-nested && cargo publish)
+(cd datafusion/functions-window && cargo publish)
 (cd datafusion/sql && cargo publish)
 (cd datafusion/optimizer && cargo publish)
 (cd datafusion/common-runtime && cargo publish)
-(cd datafusion/catalog && cargo publish)
 (cd datafusion/physical-plan && cargo publish)
+(cd datafusion/catalog && cargo publish)
 (cd datafusion/physical-optimizer && cargo publish)
 (cd datafusion/core && cargo publish)
 (cd datafusion/proto-common && cargo publish)