doc: Add basic info

README.md

@@ -1,4 +1,42 @@
-## eternity2-solver
+# eternity2-solver
 
-This is a solver for (reduced versions of) the [Eternity II](https://en.wikipedia.org/wiki/Eternity_II_puzzle)
+This is a solver library for (reduced versions of) the [Eternity II](https://en.wikipedia.org/wiki/Eternity_II_puzzle)
 puzzle. It is written in Java and uses a SAT solver ([Sat4j](http://www.sat4j.org/)).
+
+## Installation
+
+Add the following dependency to your `pom.xml`:
+
+```xml
+<dependency>
+    <groupId>re.belv</groupId>
+    <artifactId>eternity2-solver</artifactId>
+    <version>1.0-SNAPSHOT</version>
+</dependency>
+```
+
+## Usage
+
+Here is an example of how to use the library:
+
+```java
+// The list of pieces (id, north color, east color, south color, west color).
+final var pieces = new Piece[]{
+                new Piece(0, 0, 1, 2, 3),
+                new Piece(1, 0, 1, 2, 3),
+                new Piece(2, 0, 1, 2, 3),
+                new Piece(3, 0, 1, 2, 3),
+        };
+
+// The board is a 2x2 grid. The bottom right piece is fixed.
+final var initialBoard = new Piece[2][2];
+initialBoard[1][1] = pieces[1].rotate(Piece.Rotation.PLUS_90);
+
+// Instantiate the solver and solve the game.
+final var solver = new Solver();
+final Iterator<Piece[][]> solutions = solver.solve(pieces, initialBoard);
+while(solutions.hasNext()){
+    final Piece[][] solution = solutions.next();
+    System.out.println(Arrays.deepToString(solution));
+}
+```