Add license and readme

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2017 krstak
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -0,0 +1,76 @@
+# In-Memory Database
+Small in-memory database. It is useful for testing and test environment. Should not be used in production.
+
+## Install
+```
+go get -u github.com/krstak/memorydb
+```
+
+## API
+
+```go
+Add      func(item interface{}, collection string) string
+FindAll  func(collection string) ([]interface{}, error)
+FindById func(id string, collection string) (interface{}, error)
+FindBy   func(field, value, collection string) (interface{}, error)
+Update   func(id string, item interface{}, collection string) error
+Remove   func(id, collection string) error
+```
+
+## Usage
+
+##### Create database
+```go
+db := memorydb.Create()
+```
+
+##### Entity to persist
+In order to save some struct in db, it should have the required field `Id` type `string`. Everything else is optional.
+```go
+type book struct {
+	Id     string
+	isbn   string
+	name   string
+	author string
+}
+```
+
+##### Write to database
+Important: Reference should be passed in.
+```go
+memBook := book{isbn: "1234567", name: "In-Memory DB", author: "Marko Krstic"}
+id := db.Add(&memBook, "books")
+```
+
+##### Find all
+Important: slice of interface{} is returned
+```go
+books, err := db.FindAll("books")
+bk := books[0].(*book)
+```
+
+##### Find by Id
+Important: interface{} is returned
+```go
+bk, err := db.FindById(id, "books")
+b := bk.(*book)
+```
+
+##### Find by custom field
+Important: interface{} is returned
+```go
+bk, err := db.FindBy("isbn", "1234567", "books")
+b := bk.(*book)
+```
+
+##### Update
+Important: Reference should be passed in.
+```go
+bk := book{isbn: "222", name: "In-Memory DB", author: "Marko Krstic"}
+err := db.Update(id, &bk, "books")
+```
+
+##### Remove
+```go
+err := db.Remove(id, "books")
+```

db.go

@@ -15,10 +15,10 @@ const (
 type Manager struct {
 	Add      func(item interface{}, collection string) string
 	FindAll  func(collection string) ([]interface{}, error)
-	FindBy   func(field, value, collection string) (interface{}, error)
 	FindById func(id string, collection string) (interface{}, error)
-	Remove   func(id, collection string) error
+	FindBy   func(field, value, collection string) (interface{}, error)
 	Update   func(id string, item interface{}, collection string) error
+	Remove   func(id, collection string) error
 }
 
 type col struct {