docs(readme): correct example in readme.md (#84) [ci skip]

sql.js:20 Uncaught (in promise) Error: table "games" has more than one primary key
    at Database../node_modules/sql.js/js/sql.js.Database.handleError (sql.js:20)
    at Database../node_modules/sql.js/js/sql.js.Database.run (sql.js:20)
    at trilogy.js:278
    at <anonymous>

Primary key duped in table "game". It is needed to remove one.

readme.md

@@ -99,11 +99,11 @@ const db = new Trilogy(':memory:', {
 
 ;(async function () {
   const games = await db.model('games', {
-    name: { type: String, primary: true },   // primary key
+    name: { type: String },
     genre: String,                           // type shorthand
     released: Date,
     awards: Array,
-    id: 'increments'                         // special type
+    id: 'increments'                         // special type, primary key
   })
 
   await games.create({