Update readme with project URLs

Author: pombredanne

README.md

@@ -1,2 +1,23 @@
 # aboutcode
- AboutCode data to document data .... about code.
+ AboutCode is an umbrella project to uncover data ... about software code:
+ 
+ - where does it come from?
+ - what is its license?
+ - is it secure, maintained, well coded?
+ All these are questions that are important to find answers to when there are million of free and open source software components available on the web.
+  
+The main homepage lives at http://aboutcode.org
+
+Each project has its own repository:
+
+- ScanCode: this the scanner to detect the origin and license of code and its dependencies as a command line tool. https://github.com/nexB/scancode-toolkit . The lead maintainer is @pombredanne
+
+- AboutCode Manager: this is a GUI-based, desktop application (based on Electron) to review the results of scans and help document conclusions. https://github.com/nexB/aboutcode-manager . The lead maintainer is @jdaguil
+
+- AtributeCode: this is a command line to document the provenance of code without changing it using a small yaml file. https://github.com/nexB/attributecode/ The lead maintainer @chinyeungli
+
+- License Expression: this is a library to parse, analyze, compare and normalize SPDX and SPDX-like license expressions using a boolean logic expression engine. See https://spdx.org/spdx-specification-21-web-version#h.jxpfx0ykyb60 to understand what an expression is. See https://github.com/nexB/license-expression for the code. The underlying boolea engine live at https://github.com/bastikr/boolean.py . Both are co-maintained by @pombredanne 
+
+- TraceCode-build: this is a tool to analyze the traced execution of a build, so you can learn which files are built into binaries and ultimately deployed in your distributed software. It uses strace https://github.com/strace/strace/ to which we contribute to trace system calls on Linux and reconstruct a build graph from syscalls to find which file is used to build a binary. Maintained by @pombredanne 
+
+-ABCD: or AboutCode Data is a simple set of convention to define data structures that all the AboutCode tools can understand and use to exachnge data together. The upcoming specification will live in this repository.