query: license sinatra 
supports: A domain-specific language (DSL) is a computer language specialized to a particular application domain. This is in contrast to a general-purpose language (GPL), which is broadly applicable across domains. There is a wide variety of DSLs, ranging from widely used languages for common domains, such as HTML for web pages, down to languages used by only one or a few pieces of software, such as Emacs Lisp for GNU Emacs and XEmacs. DSLs can be further subdivided by the kind of language, and include domain-specific "markup" languages, domain-specific "modeling" languages (more generally, specification languages), and domain-specific "programming" languages. Special-purpose computer languages have always existed in the computer age, but the term "domain-specific language" has become more popular due to the rise of domain-specific modeling. Simpler DSLs, particularly ones used by a single application, are sometimes informally called mini-languages. GNU Emacs is the most popular and most ported Emacs text editor. It was created by GNU Project founder Richard Stallman. In common with other varieties of Emacs, GNU Emacs is extensible using a Turing complete programming language. GNU Emacs has been called "the most powerful text editor available today." With proper support from the underlying system, GNU Emacs is able to display files in multiple character sets, and has been able to simultaneously display most human languages since at least 1999. Throughout its history, GNU Emacs has been a central component of the GNU project, and a flagship of the free software movement. GNU Emacs is sometimes abbreviated as GNUMACS, especially to differentiate it from other EMACS variants. The tag line for GNU Emacs is "the extensible self-documenting text editor". XEmacs is a graphical- and console-based text editor which runs on almost any Unix-like operating system as well as Microsoft Windows. XEmacs is a fork, based on a version of GNU Emacs from the late 1980s. Any user can download, use, and modify XEmacs as free software available under the GNU General Public License version 2 or any later version. Ruby on Rails, or simply Rails, is a server-side web application framework written in Ruby under the MIT License. Rails is a modelviewcontroller (MVC) framework, providing default structures for a database, a web service, and web pages. It encourages and facilitates the use of web standards such as JSON or XML for data transfer, and HTML, CSS and JavaScript for display and user interfacing. In addition to MVC, Rails emphasizes the use of other well-known software engineering patterns and paradigms, including convention over configuration (CoC), don't repeat yourself (DRY), and the active record pattern. Sinatra is a free and open source software web application library and domain - specific language written in Ruby . It is an alternative to other Ruby web application frameworks such as Ruby on Rails , Merb , Nitro , and Camping . It is dependent on the Rack web server interface . Designed and developed by Blake Mizerany , Sinatra is small and flexible . It does not follow the typical model -- view -- controller pattern used in other frameworks , such as Ruby on Rails . Instead , Sinatra focuses on `` quickly creating web - applications in Ruby with minimal effort . '' Some notable companies and institutions that use Sinatra include Apple , BBC , the British Government 's Government Digital Service , LinkedIn , the National Security Agency , Engine Yard , Heroku , GitHub , and Songbird . Travis CI provides much of the financial support for Sinatra 's development . Sinatra was created and open - sourced in 2007 . The MIT License is a permissive free software license originating at the Massachusetts Institute of Technology (MIT). As a permissive license, it puts only very limited restriction on reuse and has, therefore, an excellent license compatibility. The MIT license permits reuse within proprietary software provided that all copies of the licensed software include a copy of the MIT License terms and the copyright notice. The MIT license is also compatible with many copyleft licenses, such as the GNU General Public License (GPL); MIT licensed software can be integrated into GPL software, but not the other way around. In computing, a web application or web app is a clientserver software application in which the client (or user interface) runs in a web browser. Common web applications include webmail, online retail sales, online auctions, wikis, instant messaging services and many other functions. A wiki is a website that provides collaborative modification of its content and structure directly from the web browser. In a typical wiki, text is written using a simplified markup language (known as "wiki markup") and often edited with the help of a rich-text editor. A wiki is run using wiki software, otherwise known as a wiki engine. There are dozens of different wiki engines in use, both standalone and part of other software, such as bug tracking systems. Some wiki engines are open source, whereas others are proprietary. Some permit control over different functions (levels of access); for example, editing rights may permit changing, adding or removing material. Others may permit access without enforcing access control. Other rules may also be imposed to organize content. A wiki engine is a type of content management system, but it differs from most other such systems, including blog software, in that the content is created without any defined owner or leader, and wikis have little implicit structure, allowing structure to emerge according to the needs of the users.
candidates: free software mit license open source proprietary software
answer: mit license