Merge pull request #7 from wowinter13/feat/readme_upd

Add more badges and details to README.md

Author: wowinter13

README.md

@@ -4,7 +4,7 @@ This package is a ruby native port of the numpy-financial package with some help
 
 The functions in this package are a scalar version of their vectorised counterparts in the [numpy-financial](https://github.com/numpy/numpy-financial) library.
 
-[![Release](https://img.shields.io/github/v/release/wowinter13/finance_rb.svg?style=flat-square)](https://github.com/wowinter13/finance_rb/releases) [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg?style=flat-square)](http://makeapullrequest.com)
+[![Release](https://img.shields.io/github/v/release/wowinter13/finance_rb.svg?style=flat-square)](https://github.com/wowinter13/finance_rb/releases) [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg?style=flat-square)](http://makeapullrequest.com) [![Maintainability](https://api.codeclimate.com/v1/badges/bbca82ad7815794c6718/maintainability)](https://codeclimate.com/github/wowinter13/finance_rb/maintainability)
 
 Currently, only some functions are ported,  
 which are as follows:  
@@ -20,4 +20,32 @@ which are as follows:
 | rate                         |     |    Computes the rate of interest per period|
 | irr                          |    ✅    |    Computes the internal rate of return|
 | npv                          |  ✅   |   Computes the net present value of a series of cash flow|
-| mirr                         |    ✅    |    Computes the modified internal rate of return|
+| mirr                         |    ✅    |    Computes the modified internal rate of return|
+
+## Installation
+
+finance_rb is available as a gem, to install it just install the gem:
+
+    gem install finance_rb
+
+If you're using Bundler, add the gem to Gemfile.
+
+    gem 'finance_rb'
+
+Run `bundle install`.
+
+## Running tests
+
+    bundle exec rspec spec/
+
+## Contributing
+
+1. Fork it ( https://github.com/wowinter13/finance_rb/fork )
+2. Create your feature branch (`git checkout -b my-new-feature`)
+3. Commit your changes (`git commit -am 'Add some feature'`)
+4. Push to the branch (`git push origin my-new-feature`)
+5. Create a new Pull Request
+
+## License
+
+MIT License. See LICENSE for details.