测试升级学员表（学员表增加一列）；增加im_lib（tcp连接）

endian11

2019-12-12 dce8fc9c184fb7fec64aaefa11a3be627a54093b

 app/src/main/java/safeluck/drive/evaluation/DB/Student.java

@@ -30,6 +30,16 @@
    @ColumnInfo(name = "sex")
    private int sex;

    public long getBegin_time() {
        return begin_time;
    }

    public void setBegin_time(long begin_time) {
        this.begin_time = begin_time;
    }

    private long begin_time;

    public Student(long stu_id, @NonNull String name, String ID, int sex) {
        this.stu_id = stu_id;
        this.name = name;