Adds license information

Author: austintoddj

readme.md

@@ -71,3 +71,7 @@ If you followed the steps up to this point correctly, you should see the followi
 #### Thanks
 
 Couldn't have done this project without the help of [Comanche](https://github.com/Comanche/). His help in refactoring the SQL search functions made this possible. Thanks!
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+#### License
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+PHP-PostgreSQL-ZipCode-Class is an open-sourced project licensed under the [MIT license](https://opensource.org/licenses/MIT).