add core concepts documentation

docs/CORE_CONCEPTS.md

@@ -2,36 +2,92 @@
 
 ## NYC Open Data
 
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-- NYC Open Data Portal
-- Socrata
-- Tyler Technologies
+NYC Open Data is free public data published by New York City agencies and other partners.
+
+The Open Data Team at the NYC Office of Technology and Innovation (OTI) oversees the program. The team works with City agencies to identify and make data available, coordinate platform operations and improvements, and promote the use of Open Data both within government and throughout NYC. Each City agency also has an Open Data Coordinator, who serves as the main point of contact for the Open Data team and the public, and works to identify, document, structure, and manage the agency’s public datasets.
+
+Website:
+- https://opendata.cityofnewyork.us/
+
+### Socrata and Tyler Technologies
+
+NYC Open Data is hosted and shared through the Socrata platform:
+
+- https://data.cityofnewyork.us/browse?sortBy=relevance&page=1&pageSize=20
+- https://dev.socrata.com/
+
+Tyler Technologies purchased Socrata in 2018:
+
+- https://www.govtech.com/biz/tyler-technologies-acquires-socrata.html
 
 ## Ruby
 
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+Ruby is a general-purpose programming language designed for simplicity and productivity.
+
+Website:
+- https://www.ruby-lang.org/en/
+
+Tutorial:
+- https://www.theodinproject.com/paths/full-stack-ruby-on-rails/courses/ruby
+
+Source Code:
+- https://github.com/ruby/ruby
 
 ## Ruby on Rails
 
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+Rails is a web application framework that includes everything needed to create database-backed web applications.
+
+Website:
+- https://rubyonrails.org/
+
+Tutorial:
+- https://www.theodinproject.com/paths/full-stack-ruby-on-rails/courses/ruby-on-rails
+
+Source Code:
+- https://github.com/rails/rails
 
 ## Postgres
 
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+PostgreSQL is a powerful, open source object-relational database system with over 35 years of active development that has earned it a strong reputation for reliability, feature robustness, and performance.
+
+Website:
+- https://www.postgresql.org/
+
+Source Code:
+- https://github.com/postgres/postgres
 
 ## Multiple databases
 
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+Ruby on Rails supports connecting to multiple databases.
+
+Documentation:
 - https://guides.rubyonrails.org/active_record_multiple_databases.html
 
 ## Kiba
 
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+Kiba is a data processing & ETL framework for Ruby.
+
+Website:
+- https://www.kiba-etl.org/
+
+Source Code:
+- https://github.com/thbar/kiba
 
 ## BI
 
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+Business Intelligence (BI) software comprises tools that collect, analyze, and visualize data from various sources to provide actionable insights for decision-making.
+
+Open source solutions include
+- Apache Superset
+- Metabase
+- and many more
 
 ## Apache Superset
 
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+Apache Superset™ is an open-source modern data exploration and visualization platform.
+
+Website:
+- https://superset.apache.org/
+
+Source Code:
+- https://github.com/apache/superset