Add License to README.md

Author: FrangSierra

README.md

@@ -249,3 +249,28 @@ public class PostAdapter extends RxFirebaseRecyclerAdapter<PostViewHolder, Post>
 
 }
 ```
+
+## License
+
+	MIT License
+
+	Copyright (c) 2016 Francisco García Sierra
+
+	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.
+