Feature/ddl migration (#1111)

* REFACTOR: use functions from ddl-help

* NEW: Default values are written to DDL

* fix testcase for sqlserver as default constraints will get names in future

* Reading DbMigration

* ADD: DbmIgrationGenerateTest

* Tables must be created first

* Sanity checks and some getters

* DdlMigration gets applied now

* ADD: Testcase and reference migration scripts

* no effective code changes: add comments

src/test/java/misc/migration/v1_0/EBasic.java

@@ -0,0 +1,116 @@
+package misc.migration.v1_0;
+
+import io.ebean.annotation.EnumValue;
+import io.ebean.annotation.Index;
+import io.ebean.annotation.NotNull;
+import misc.migration.v1_1.EUser;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.ManyToOne;
+import javax.persistence.Table;
+import java.sql.Timestamp;
+
+@Entity
+@Table(name = "migtest_e_basic")
+public class EBasic {
+
+  public enum Status {
+    @EnumValue("N")
+    NEW,
+
+    @EnumValue("A")
+    ACTIVE,
+
+    @EnumValue("I")
+    INACTIVE,
+  }
+
+  @Id
+  Integer id;
+
+  Status status;
+  
+  String name;
+
+  String description;
+
+  Timestamp someDate;
+  
+  boolean old_boolean;
+
+  Boolean old_boolean2;
+  
+  @ManyToOne
+  ERef eref;
+  
+  
+  // test add & remove indices
+  @Index
+  String indextest1;
+  
+  @Index(unique = true)
+  String indextest2;
+  
+  String indextest3;
+  
+  String indextest4;
+  
+  @Index(unique = false)
+  String indextest5;
+  
+  @Index(unique = true)
+  String indextest6;
+  
+  @NotNull
+  int user_id;
+  
+  public EBasic() {
+
+  }
+
+  public EBasic(String name) {
+    this.name = name;
+  }
+
+  public Integer getId() {
+    return id;
+  }
+
+  public void setId(Integer id) {
+    this.id = id;
+  }
+
+  public Status getStatus() {
+    return status;
+  }
+
+  public void setStatus(Status status) {
+    this.status = status;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+  public void setName(String name) {
+    this.name = name;
+  }
+
+  public String getDescription() {
+    return description;
+  }
+
+  public void setDescription(String description) {
+    this.description = description;
+  }
+
+  public Timestamp getSomeDate() {
+    return someDate;
+  }
+
+  public void setSomeDate(Timestamp someDate) {
+    this.someDate = someDate;
+  }
+
+}