Moved shaders to standalone source file

assets/shaders/shader.frag

@@ -0,0 +1,8 @@
+#version 150 core
+
+in vec3 _color;
+out vec4 color;
+
+void main() {
+    color = vec4(_color, 1.0);
+}

assets/shaders/shader.vert

@@ -0,0 +1,10 @@
+#version 150 core
+
+in vec2 position;
+in vec3 color;
+out vec3 _color;
+
+void main() {
+    _color = color;
+    gl_Position = vec4(position, 0.0, 1.0);
+}