add basic readme.md file

T2/README.md

+# STEAMDB V0.0.1
+### dependencies: latest version of ruby (2.5.0), active\_record gem, sqlite3 gem
+
+## Introduction
+Hi! This is a project made for the second evaluation of the Tópicos em Programação de Computadores (CI320) course at Universidade Federal do Paraná in Brazil. 
+
+This project simulates a simplified working database management system similar to sqlite3. It was implemented in the Ruby language and it uses the Active Record gem to establish a connection with sqlite3.
+
+## How to use
+### Creating the database
+To create the tables defined in the schema.rb file, run: 
+$ ruby schema.rb
+
+The steamdb.sqlite3 file on this repository already contains a few example rows to simplify the testing of the different functionalities. To reset the entire database, simply delete the steamdb.sqlite3 file and run the schema.rb file again. 
+
+The models for each object type are defined in the models.rb file. This database system implements 1 to 1, 1 to n and n to n relationships.
+
+### Running SteamDB
+To run SteamDB, just enter the following command on your terminal:
+$ ruby steamdb.rb
+
+### Instructions
+This program contains four basic functionalities:
+ - insere (add a new element)
+ - exclui (remove one or more elements)
+ - altera (update one or more elements)
+ - lista (list all the elements of a table)
+
+### Command syntax