Resolve "Create security and transaction annotations"

Closes #15 (closed)

src/main/java/cz/muni/ics/kypo/training/adaptive/annotations/security/IsAdmin.java

+package cz.muni.ics.kypo.training.adaptive.annotations.security;
+
+import org.springframework.security.access.prepost.PreAuthorize;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * The custom annotation <i>@IsAdmin<i/>. All methods annotated with this annotation expect the user has a role <strong>ROLE_TRAINING_ADMINISTRATOR<strong/>.
+ */
+@Target(ElementType.METHOD)
+@Retention(RetentionPolicy.RUNTIME)
+@PreAuthorize("hasAuthority(T(cz.muni.ics.kypo.training.adaptive.enums.RoleTypeSecurity).ROLE_TRAINING_ADMINISTRATOR)")
+public @interface IsAdmin {}