Do not force to pass the databaseName

See: #46

README.md

@@ -82,6 +82,11 @@ module.exports = {
 };
 ````
 
+Alternatively, you can also encode your database name in the url (and leave out the `databaseName` property):
+````
+        url: "mongodb://localhost:27017/YOURDATABASE",
+````
+
 ### Creating a new migration script
 To create a new database migration script, just run the ````migrate-mongo create [description]```` command.
 

lib/env/database.js

@@ -13,13 +13,6 @@ module.exports = {
       throw new Error("No `url` defined in config file!");
     }
 
-    if (!databaseName) {
-      throw new Error(
-        "No `databaseName` defined in config file! This is required since migrate-mongo v3. " +
-          "See https://github.com/seppevs/migrate-mongo#initialize-a-new-project"
-      );
-    }
-
     const client = await MongoClient.connect(
       url,
       options

test/env/database.test.js

@@ -86,19 +86,6 @@ describe("database", () => {
       }
     });
 
-    it("should yield an error when no databaseName is defined in the config file", async () => {
-      delete configObj.mongodb.databaseName;
-      try {
-        await database.connect();
-        expect.fail("Error was not thrown");
-      } catch (err) {
-        expect(err.message).to.equal(
-          "No `databaseName` defined in config file! This is required since migrate-mongo v3. " +
-            "See https://github.com/seppevs/migrate-mongo#initialize-a-new-project"
-        );
-      }
-    });
-
     it("should yield an error when unable to connect", async () => {
       mongodb.MongoClient.connect.returns(
         Promise.reject(new Error("Unable to connect"))