Complete the README [skip ci]

README.md

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 [0]: https://circleci.com/gh/jpvillaisaza/licensor
 [1]: https://circleci.com/gh/jpvillaisaza/licensor.svg?style=svg
 
+![][2]
+![][3]
+
+[2]: https://www.stackage.org/package/licensor/badge/lts
+[3]: https://www.stackage.org/package/licensor/badge/nightly
+
+Licensor is a program that generates a report of the dependencies and
+transitive dependencies of a Haskell project and their licenses.
+
+## Description
+
+Choosing a license for a software project or determining whether a
+particular dependency can be added to a project can be projects
+themselves. Unless starting from scratch, programmers should consider
+the licenses of the dependencies and transitive dependencies of their
+projects to make informed decisions and avoid license compatibility
+issues.
+
+Of course, this is just a starting point. "Beyond (...) general
+observations, it is difficult, if not impossible, to provide precise
+guidance about what licenses may or may not be compatible with each
+other. (...) Programmers who are considering combining code governed
+by two or more different licenses should proceed cautiously" (Andrew
+M. St. Laurent).
+
+## Disclaimer
+
+Licensor is not a lawyer and does not provide legal advice.
+
+For more information about licenses and license compatibility issues,
+read the text of the licenses or consult with a lawyer before making
+any decision.
+
+## Related programs
+
+Licensor is not the only license compatibility helper for Haskell:
+
+- Licensor uses a Cabal library and Stack program approach for
+  detecting licenses and listing dependencies, respectively. For a
+  Cabal library and program approach, consider using
+  the [cabal-dependency-licenses][rp-01] program.
+
+[rp-01]: https://hackage.haskell.org/package/cabal-dependency-licenses
+
+## Installation and usage
+
+To install Licensor, use Cabal:
+
+```
+$ cabal update && cabal install licensor
+```
+
+Then, run the `licensor` executable inside a Haskell project:
+
+```
+$ licensor
+```
+
+To see the license report for Licensor, clone the repository:
+
+```
+$ git clone https://github.com/jpvillaisaza/licensor
+```
+
+And run `licensor` inside the project:
+
+```
+$ cd licensor/ && licensor
+```
+
+Or build and run `licensor` inside the project:
+
+```
+$ cd licensor/ && stack build --exec licensor
+```
+
+For more information, run `licensor --help`:
+
+```
+licensor 0.2.0
+
+licensor [OPTIONS]
+
+Common flags:
+  -? --help             Display help message
+  -V --version          Print version information
+     --numeric-version  Print just the version number
+```
+
+## Notes
+
+### Dependencies
+
+Licensor uses the Stack program to list dependencies for a Haskell
+project. A future enhancement could be to use the Stack library.
+
+### Licenses and license detection
+
+Licensor uses the Cabal library to detect the license of a Haskell
+project and its dependencies (including transitive dependencies). To
+do so, it uses the license field in the package description. A future
+enhancement could be to use both the license and licence file fields
+in the package description.
+
+Cabal provides an enumeration of common open source and free software
+licenses. These are the licenses that appear in the reports generated
+by Licensor:
+
+License                   | Description
+------------------------- | -------------------------
+GPL                       | GNU General Public License
+AGPL                      | GNU Affero General Public License
+LGPL                      | GNU Lesser General Public License
+BSD2                      | BSD 2-Clause License
+BSD3                      | BSD 3-Clause License
+BSD4                      | BSD 4-Clause License
+MIT                       | MIT License
+ISC                       | ISC License
+MPL                       | Mozilla Public License
+Apache                    | Apache License
+PublicDomain              | Public domain
+AllRightsReserved         | All rights reserved
+UnspecifiedLicense        | Unspecified license (All rights reserved)
+OtherLicense              | Other license
+UnknownLicense            | Unknown license
+
+## Contribution guidelines
+
+Feel free to create issues for reporting bugs and suggesting
+enhancements, or to fork the repository and open a pull request.
+
 ## License
 
 Licensor is licensed under the MIT License.
+See [LICENSE.md](LICENSE.md).
+
+### License report
+
+Licensor (0.2.0) depends on the following libraries:
+
+Library                   | License
+------------------------- | -------------------------
+base                      | BSD3
+bytestring                | BSD3
+Cabal                     | BSD3
+cmdargs                   | BSD3
+containers                | BSD3
+directory                 | BSD3
+http-conduit              | BSD3
+process                   | BSD3
+
+And the following licenses (including transitive dependencies):
+
+License                   | Number of libraries
+------------------------- | -------------------------
+BSD3                      | 68
+MIT                       | 7
+
+(Tested with Licensor 0.2.0, Stack 1.2.0, and LTS 7.0.)
+
+## Additional resources
+
+- [Choose a License](http://choosealicense.com/)
+- [License compatibility][ar-01]
+- [Understanding open source and free software licensing][ar-02]
+  (Andrew M. St. Laurent)
+
+[ar-01]: https://en.wikipedia.org/wiki/License_compatibility
+[ar-02]: http://www.oreilly.com/openbook/osfreesoft/book/